diff --git a/src/damage.cpp b/src/damage.cpp
index aa8a75250abfb..7f077ad55e267 100644
--- a/src/damage.cpp
+++ b/src/damage.cpp
@@ -98,7 +98,7 @@ resistances::resistances()
     resist_vals.fill( 0 );
 }
 
-resistances::resistances( item &armor, bool to_self )
+resistances::resistances( const item &armor, bool to_self )
 {
     // Armors protect, but all items can resist
     if( to_self || armor.is_armor() ) {
diff --git a/src/damage.h b/src/damage.h
index 5b9b2a284c785..41c0233701559 100644
--- a/src/damage.h
+++ b/src/damage.h
@@ -34,7 +34,7 @@ struct damage_unit {
     float res_mult;
     float damage_multiplier;
 
-    damage_unit( damage_type dt, float a, int rp, float rm, float mul ) :
+    damage_unit( damage_type dt, float a, int rp = 0, float rm = 1.0f, float mul = 1.0f ) :
         type( dt ), amount( a ), res_pen( rp ), res_mult( rm ), damage_multiplier( mul ) { }
 };
 
@@ -69,7 +69,7 @@ struct resistances {
     resistances();
 
     // If to_self is true, we want armor's own resistance, not one it provides to wearer
-    resistances( item &armor, bool to_self = false );
+    resistances( const item &armor, bool to_self = false );
     resistances( monster &monster );
     void set_resist( damage_type dt, float amount );
     float type_resist( damage_type dt ) const;
diff --git a/src/field.cpp b/src/field.cpp
index 64779f276c31c..49365c3f0ca9d 100644
--- a/src/field.cpp
+++ b/src/field.cpp
@@ -88,7 +88,7 @@ void game::init_fields()
         {
             "fd_web",
             {_("cobwebs"),_("webs"), _("thick webs")}, '}', 2,
-            {c_white, c_white, c_white}, {true, true, false},{false, false, false}, 0,
+            {c_white, c_white, c_white}, {true, true, false},{true, true, true}, 0,
             {0,0,0},
             SOLID
         },
@@ -120,7 +120,7 @@ void game::init_fields()
         {
             "fd_sludge",
             {_("thin sludge trail"), _("sludge trail"), _("thick sludge trail")}, '5', 2,
-            {c_ltgray, c_dkgray, c_black}, {true, true, true}, {false, false, false}, HOURS(6),
+            {c_ltgray, c_dkgray, c_black}, {true, true, true}, {true, true, true}, HOURS(6),
             {0,0,0},
             LIQUID
         },
@@ -151,7 +151,7 @@ void game::init_fields()
         {
             "fd_toxic_gas",
             {_("hazy cloud"),_("toxic gas"),_("thick toxic gas")}, '8', 8,
-            {c_white, c_ltgreen, c_green}, {true, false, false},{false, true, true}, MINUTES(90),
+            {c_white, c_ltgreen, c_green}, {true, false, false},{true, true, true}, MINUTES(90),
             {0,0,0},
             GAS
         },
@@ -207,7 +207,7 @@ void game::init_fields()
         {
             "fd_fatigue",
             {_("odd ripple"), _("swirling air"), _("tear in reality")}, '*', 8,
-            {c_ltgray, c_dkgray, c_magenta},{true, true, false},{false, false, false},  0,
+            {c_ltgray, c_dkgray, c_magenta},{true, true, false},{true, true, true},  0,
             {0,0,0},
             PNULL
         },
@@ -348,7 +348,7 @@ void game::init_fields()
         {
             "fd_relax_gas",
             {_("hazy cloud"),_("sedative gas"),_("relaxation gas")}, '.', 8,
-            { c_white, c_pink, c_cyan }, { true, true, true }, { false, true, true }, MINUTES(50),
+            { c_white, c_pink, c_cyan }, { true, true, true }, { true, true, true }, MINUTES(50),
             {0,0,0},
             GAS
         },
@@ -396,7 +396,7 @@ void game::init_fields()
         {
             "fd_fungicidal_gas",
             {_("hazy cloud"),_("fungicidal gas"),_("thick fungicidal gas")}, '8', 8,
-            {c_white, c_ltgray, c_dkgray}, {true, true, false}, {false, true, true}, MINUTES(90),
+            {c_white, c_ltgray, c_dkgray}, {true, true, false}, {true, true, true}, MINUTES(90),
             {0,0,0},
             GAS
         }
diff --git a/src/game.cpp b/src/game.cpp
index 27f177346f200..af8ec83895d5c 100644
--- a/src/game.cpp
+++ b/src/game.cpp
@@ -12024,6 +12024,24 @@ bool game::walk_move( const tripoint &dest_loc )
                 !query_yn( _("Really step onto that %s?"), tr.name.c_str() ) ) {
                 return true;
             }
+
+            if( m.has_flag( "ROUGH", dest_loc ) && !m.has_flag( "ROUGH", u.pos() ) && !boardable &&
+                ( u.get_armor_bash( bp_foot_l ) < 5 || u.get_armor_bash( bp_foot_r ) < 5 ) &&
+                !query_yn( _( "Really step onto that %s?" ), m.name( dest_loc ).c_str() ) ) {
+                return true;
+            } else if( m.has_flag( "SHARP", dest_loc ) && !m.has_flag( "SHARP", u.pos() ) && !boardable &&
+                       u.dex_cur < 78 ) {
+                static const std::set< body_part > check = {
+                    bp_eyes, bp_mouth, bp_head, bp_leg_l, bp_leg_r, bp_foot_l, bp_foot_r, bp_arm_l, bp_arm_r,
+                    bp_hand_l, bp_hand_r, bp_torso
+                };
+                if( !std::all_of( check.begin(), check.end(), [this]( body_part bp ) {
+                return u.immune_to( bp, { DT_CUT, 10 } );
+                } ) && !query_yn( _( "Really step onto that %s?" ), m.name( dest_loc ).c_str() ) ) {
+                    return true;
+                }
+            }
+
         }
     }
 
diff --git a/src/item.cpp b/src/item.cpp
index 92645f20fd4fc..f9b5bb1362d92 100644
--- a/src/item.cpp
+++ b/src/item.cpp
@@ -2,6 +2,7 @@
 
 #include "advanced_inv.h"
 #include "player.h"
+#include "damage.h"
 #include "output.h"
 #include "skill.h"
 #include "bionics.h"
@@ -3168,6 +3169,14 @@ int item::chip_resistance( bool worst ) const
     return res;
 }
 
+void item::mitigate_damage( damage_unit &du ) const
+{
+    const resistances res = resistances( *this );
+    const float mitigation = res.get_effective_resist( du );
+    du.amount -= mitigation;
+    du.amount = std::max( 0.0f, du.amount );
+}
+
 int item::damage_resist( damage_type dt, bool to_self ) const
 {
     switch( dt ) {
diff --git a/src/item.h b/src/item.h
index 7d4eb56a380c3..a434a2b58b304 100644
--- a/src/item.h
+++ b/src/item.h
@@ -16,6 +16,7 @@
 #include "string_id.h"
 #include "line.h"
 #include "item_location.h"
+#include "damage.h"
 #include "debug.h"
 
 class game;
@@ -652,6 +653,11 @@ class item : public JsonSerializer, public JsonDeserializer, public visitable<it
     int fire_resist( bool to_self = false ) const;
     /*@}*/
 
+    /**
+     * Assuming that @du hit the armor, reduce @du based on the item's resistance to the damage type.
+     * This will never reduce @du.amount below 0.
+     */
+     void mitigate_damage( damage_unit &du ) const;
     /**
      * Resistance provided by this item against damage type given by an enum.
      */
diff --git a/src/player.cpp b/src/player.cpp
index 077a82ba2c661..aeec36b518d61 100644
--- a/src/player.cpp
+++ b/src/player.cpp
@@ -4600,6 +4600,26 @@ void player::on_hurt( Creature *source, bool disturb /*= true*/ )
     }
 }
 
+bool player::immune_to( body_part bp, damage_unit dam ) const
+{
+    if( dam.type == DT_HEAT ) {
+        return false; // No one is immune to fire
+    }
+    if( has_trait( "DEBUG_NODMG" ) || is_immune_damage( dam.type ) ) {
+        return true;
+    }
+
+    passive_absorb_hit( bp, dam );
+
+    for( const item &cloth : worn ) {
+        if( cloth.get_coverage() == 100 && cloth.covers( bp ) ) {
+            cloth.mitigate_damage( dam );
+        }
+    }
+
+    return dam.amount <= 0;
+}
+
 dealt_damage_instance player::deal_damage(Creature* source, body_part bp, const damage_instance& d)
 {
     if( has_trait( "DEBUG_NODMG" ) ) {
@@ -12182,12 +12202,7 @@ bool player::armor_absorb( damage_unit& du, item& armor )
     }
 
     // TODO: add some check for power armor
-
-    const auto res = resistances(armor);
-    const float effective_resist = res.get_effective_resist(du);
-    // Amount of damage mitigated
-    const float mitigation = std::min(effective_resist, du.amount);
-    du.amount -= mitigation; // mitigate the damage first
+    armor.mitigate_damage( du );
 
     // We want armor's own resistance to this type, not the resistance it grants
     const int armors_own_resist = armor.damage_resist( du.type, true );
@@ -12249,6 +12264,63 @@ bool player::armor_absorb( damage_unit& du, item& armor )
     return armor.damage >= 5;
 }
 
+float player::bionic_armor_bonus( body_part bp, damage_type dt ) const
+{
+    float result = 0.0f;
+    // We only check the passive bionics
+    if( has_bionic( "bio_carbon" ) ) {
+        if( dt == DT_BASH ) {
+            result += 2;
+        } else if( dt == DT_CUT ) {
+            result += 4;
+        } else if( dt == DT_STAB ) {
+            result += 3.2;
+        }
+    }
+    //all the other bionic armors reduce bash/cut/stab by 3/3/2.4
+    // Map body parts to a set of bionics that protect it
+    // @todo: JSONize passive bionic armor instead of hardcoding it
+    static const std::map< body_part, std::string > armor_bionics = {
+    { bp_head, { "bio_armor_head" } },
+    { bp_arm_l, { "bio_armor_arms" } },
+    { bp_arm_r, { "bio_armor_arms" } },
+    { bp_torso, { "bio_armor_torso" } },
+    { bp_leg_l, { "bio_armor_legs" } },
+    { bp_leg_r, { "bio_armor_legs" } },
+    { bp_eyes, { "bio_armor_eyes" } }
+    };
+    auto iter = armor_bionics.find( bp );
+    if( iter != armor_bionics.end() ) {
+        if( has_bionic( iter->second ) ) {
+            if( dt == DT_BASH || dt == DT_CUT ) {
+                result += 3;
+            } else if( dt == DT_STAB ) {
+                result += 2.4;
+            }
+        }
+    }
+    return result;
+}
+
+void player::passive_absorb_hit( body_part bp, damage_unit &du ) const
+{
+    du.amount -= bionic_armor_bonus( bp, du.type ); //Check for passive armor bionics
+    // >0 check because some mutations provide negative armor
+        if( du.amount > 0.0f ) {
+            // Horrible hack warning!
+            // Get rid of this as soon as CUT and STAB are split
+            if( du.type == DT_STAB ) {
+                damage_unit du_copy = du;
+                du_copy.type = DT_CUT;
+                du.amount -= 0.8f * mutation_armor( bp, du_copy );
+            } else {
+                du.amount -= mutation_armor( bp, du );
+            }
+        }
+        du.amount -= mabuff_armor_bonus( du.type );
+        du.amount = std::max( 0.0f, du.amount );
+}
+
 void player::absorb_hit(body_part bp, damage_instance &dam) {
     std::list<item> worn_remains;
     bool armor_destroyed = false;
@@ -12260,7 +12332,7 @@ void player::absorb_hit(body_part bp, damage_instance &dam) {
             continue;
         }
 
-        // CBMs absorb damage first before hitting armor
+        // The bio_ads CBM absorbs damage before hitting armor
         if( has_active_bionic("bio_ads") ) {
             if( elem.amount > 0 && power_level > 24 ) {
                 if( elem.type == DT_BASH ) {
@@ -12327,96 +12399,7 @@ void player::absorb_hit(body_part bp, damage_instance &dam) {
             }
         }
 
-        // Next, apply reductions from bionics and traits.
-        if( has_bionic("bio_carbon") ) {
-            switch (elem.type) {
-            case DT_BASH:
-                elem.amount -= 2;
-                break;
-            case DT_CUT:
-                elem.amount -= 4;
-                break;
-            case DT_STAB:
-                elem.amount -= 3.2;
-                break;
-            default:
-                break;
-            }
-        }
-        if( bp == bp_head && has_bionic("bio_armor_head") ) {
-            switch (elem.type) {
-            case DT_BASH:
-            case DT_CUT:
-                elem.amount -= 3;
-                break;
-            case DT_STAB:
-                elem.amount -= 2.4;
-                break;
-            default:
-                break;
-            }
-        } else if( (bp == bp_arm_l || bp == bp_arm_r) && has_bionic("bio_armor_arms") ) {
-            switch (elem.type) {
-            case DT_BASH:
-            case DT_CUT:
-                elem.amount -= 3;
-                break;
-            case DT_STAB:
-                elem.amount -= 2.4;
-                break;
-            default:
-                break;
-            }
-        } else if( bp == bp_torso && has_bionic("bio_armor_torso") ) {
-            switch (elem.type) {
-            case DT_BASH:
-            case DT_CUT:
-                elem.amount -= 3;
-                break;
-            case DT_STAB:
-                elem.amount -= 2.4;
-                break;
-            default:
-                break;
-            }
-        } else if( (bp == bp_leg_l || bp == bp_leg_r) && has_bionic("bio_armor_legs") ) {
-            switch (elem.type) {
-            case DT_BASH:
-            case DT_CUT:
-                elem.amount -= 3;
-                break;
-            case DT_STAB:
-                elem.amount -= 2.4;
-                break;
-            default:
-                break;
-            }
-        } else if( bp == bp_eyes && has_bionic("bio_armor_eyes") ) {
-            switch (elem.type) {
-            case DT_BASH:
-            case DT_CUT:
-                elem.amount -= 3;
-                break;
-            case DT_STAB:
-                elem.amount -= 2.4;
-                break;
-            default:
-                break;
-            }
-        }
-
-        // >0 check because some mutations provide negative armor
-        if( elem.amount > 0.0f ) {
-            // Horrible hack warning!
-            // Get rid of this as soon as CUT and STAB are split
-            if( elem.type == DT_STAB ) {
-                damage_unit elem_copy = elem;
-                elem_copy.type = DT_CUT;
-                elem.amount -= 0.8f * mutation_armor( bp, elem_copy );
-            } else {
-                elem.amount -= mutation_armor( bp, elem );
-            }
-        }
+        passive_absorb_hit( bp, elem );
 
         if( elem.type == DT_BASH ) {
             if( has_trait( "LIGHT_BONES" ) ) {
@@ -12427,8 +12410,6 @@ void player::absorb_hit(body_part bp, damage_instance &dam) {
             }
         }
 
-        elem.amount -= mabuff_armor_bonus( elem.type );
-
         elem.amount = std::max( elem.amount, 0.0f );
     }
     for( item& remain : worn_remains ) {
diff --git a/src/player.h b/src/player.h
index a033bbbd664bc..35994a5562ac1 100644
--- a/src/player.h
+++ b/src/player.h
@@ -514,6 +514,18 @@ class player : public Character, public JsonSerializer, public JsonDeserializer
          * @return true if the armor was completely destroyed (and the item must be deleted).
          */
         bool armor_absorb( damage_unit &du, item &armor );
+        /**
+         * Check for passive bionics that provide armor, and returns the armor bonus
+         * This is called from player::passive_absorb_hit
+         */
+         float bionic_armor_bonus( body_part bp, damage_type dt ) const;
+        /**
+         * Check for relevant passive, non-clothing that can absorb damage, and reduce @ref du
+         * Only flat bonuses are checked here. Multiplicative ones are checked in player::absorb_hit
+         * @ref du.amount will never be reduced below 0
+         * This is called from @ref player::absorb_hit
+         */
+         void passive_absorb_hit( body_part bp, damage_unit &du ) const;
         /** Runs through all bionics and armor on a part and reduces damage through their armor_absorb */
         void absorb_hit(body_part bp, damage_instance &dam) override;
         /** Called after the player has successfully dodged an attack */
@@ -625,6 +637,11 @@ class player : public Character, public JsonSerializer, public JsonDeserializer
         /** Returns a value used when attempting to intimidate NPC's */
         int intimidation() const;
 
+        /**
+         * Returns true if it is impossible for @ref dam to reduce the player's HP on his/her @ref bp
+         * @warning Only HP is accounted for- not damaged clothing, pain, status effects, etc.
+         */
+        bool immune_to( body_part bp, damage_unit dam ) const;
         /** Calls Creature::deal_damage and handles damaged effects (waking up, etc.) */
         dealt_damage_instance deal_damage(Creature *source, body_part bp, const damage_instance &d) override;
         /** Actually hurt the player, hurts a body_part directly, no armor reduction */