diff --git a/app/assets/javascripts/workers/worker_world.js b/app/assets/javascripts/workers/worker_world.js
index 9b6264173..a1c4baf0f 100644
--- a/app/assets/javascripts/workers/worker_world.js
+++ b/app/assets/javascripts/workers/worker_world.js
@@ -266,7 +266,6 @@ self.enableFlowOnThangSpell = function (thangID, spellID, userCodeMap) {
 self.setupDebugWorldToRunUntilFrame = function (args) {
     self.debugPostedErrors = {};
     self.debugt0 = new Date();
-    self.debugPostedErrors = false;
     self.logsLogged = 0;
 
     var stringifiedUserCodeMap = JSON.stringify(args.userCodeMap);
@@ -324,7 +323,6 @@ self.debugAbort = function () {
 self.runWorld = function runWorld(args) {
   self.postedErrors = {};
   self.t0 = new Date();
-  self.postedErrors = false;
   self.logsLogged = 0;
 
   try {
@@ -394,6 +392,7 @@ self.onWorldError = function onWorldError(error) {
   }
   else {
     console.log("Non-UserCodeError:", error.toString() + "\n" + error.stack || error.stackTrace);
+    self.postMessage({type: 'non-user-code-problem', problem: {message: error.toString()}});
   }
   /*  We don't actually have the recoverable property any more; hmm
   if(!error.recoverable) {
diff --git a/app/lib/Angel.coffee b/app/lib/Angel.coffee
index 2014e6471..fbdb252db 100644
--- a/app/lib/Angel.coffee
+++ b/app/lib/Angel.coffee
@@ -71,6 +71,14 @@ module.exports = class Angel extends CocoClass
       when 'user-code-problem'
         Backbone.Mediator.publish 'god:user-code-problem', problem: event.data.problem
 
+      # We have to abort like an infinite loop if we see one of these; they're not really recoverable
+      when 'non-user-code-problem'
+        Backbone.Mediator.publish 'god:non-user-code-problem', problem: event.data.problem
+        if @shared.firstWorld
+          @infinitelyLooped()  # For now, this should do roughly the right thing if it happens during load.
+        else
+          @fireWorker()
+
       # Either the world finished simulating successfully, or we abort the worker.
       when 'new-world'
         @beholdWorld event.data.serialized, event.data.goalStates
diff --git a/app/views/play/level/tome/spell_view.coffee b/app/views/play/level/tome/spell_view.coffee
index f42ecb121..04851959e 100644
--- a/app/views/play/level/tome/spell_view.coffee
+++ b/app/views/play/level/tome/spell_view.coffee
@@ -35,6 +35,7 @@ module.exports = class SpellView extends View
     'surface:coordinate-selected': 'onCoordinateSelected'
     'god:new-world-created': 'onNewWorld'
     'god:user-code-problem': 'onUserCodeProblem'
+    'god:non-user-code-problem': 'onNonUserCodeProblem'
     'tome:manual-cast': 'onManualCast'
     'tome:reload-code': 'onCodeReload'
     'tome:spell-changed': 'onSpellChanged'
@@ -441,9 +442,18 @@ module.exports = class SpellView extends View
       @lastUpdatedAetherSpellThang = null  # force a refresh without a re-transpile
       @updateAether false, false
 
+  onNonUserCodeProblem: (e) ->
+    return unless @spellThang
+    problem = @spellThang.aether.createUserCodeProblem type: 'runtime', kind: 'Unhandled', message: "Unhandled error: #{e.problem.message}"
+    @spellThang.aether.addProblem problem
+    @spellThang.castAether?.addProblem problem
+    @lastUpdatedAetherSpellThang = null  # force a refresh without a re-transpile
+    @updateAether false, false  # TODO: doesn't work, error doesn't display
+
   onInfiniteLoop: (e) ->
     return unless @spellThang
     @spellThang.aether.addProblem e.problem
+    @spellThang.castAether?.addProblem e.problem
     @lastUpdatedAetherSpellThang = null  # force a refresh without a re-transpile
     @updateAether false, false