external escape hatch controller

source/contracts/IController.sol

@@ -10,4 +10,5 @@ contract IController {
     function onlyInEmergency() public view returns(bool);
     function getAugur() public view returns (IAugur);
     function getTimestamp() public view returns (uint256);
+    function emergencyStop() public returns (bool);
 }

source/contracts/external/EscapeHatchController.sol

@@ -0,0 +1,23 @@
+pragma solidity 0.4.20;
+
+import 'IController.sol';
+import 'libraries/Ownable.sol';
+
+
+contract EscapeHatchController is Ownable {
+    IController public controller;
+
+    function setController(IController _controller) public onlyOwner returns (bool) {
+        controller = _controller;
+        return true;
+    }
+
+    function emergencyStop() public onlyOwner returns (bool) {
+        controller.emergencyStop();
+        return true;
+    }
+
+    function onTransferOwnership(address, address) internal returns (bool) {
+        return true;
+    }
+}

tests/test_escape_hatch_controller.py

@@ -0,0 +1,23 @@
+from ethereum.tools import tester
+from ethereum.tools.tester import TransactionFailed
+from utils import captureFilteredLogs, bytesToHexString, AssertLog, TokenDelta
+from pytest import raises, fixture
+
+def test_escape_hatch_controller(contractsFixture, universe, controller):
+    escapeHatchController = contractsFixture.upload('external/EscapeHatchController.sol')
+    assert escapeHatchController.setController(controller.address)
+    assert escapeHatchController.controller() == controller.address
+    assert escapeHatchController.getOwner() == bytesToHexString(tester.a0)
+
+    # transfer ownership of controller to the escape hatch controller
+    assert controller.transferOwnership(escapeHatchController.address)
+    assert controller.owner() == escapeHatchController.address
+
+    # Pull escape hatch
+    assert escapeHatchController.emergencyStop()
+    assert controller.stopped()
+
+
+@fixture
+def controller(contractsFixture, kitchenSinkSnapshot):
+    return contractsFixture.contracts['Controller']