diff --git a/app/ecs/components/collider.js b/app/ecs/components/collider.js
index 9a265b0..de74c66 100644
--- a/app/ecs/components/collider.js
+++ b/app/ecs/components/collider.js
@@ -46,13 +46,19 @@ export default class Collider extends Component {
             const script = this.$$collisionEnd.clone();
             script.context.other = otherEntity;
             script.context.pair = [body, otherBody];
-            thisEntity.Ticking.add(script.ticker());
+            const ticker = script.ticker();
+            ecs.addDestructionDependency(thisEntity.id, ticker);
+            ecs.addDestructionDependency(otherEntity.id, ticker);
+            thisEntity.Ticking.add(ticker);
           }
           if (other.$$collisionEnd) {
             const script = other.$$collisionEnd.clone();
             script.context.other = thisEntity;
             script.context.pair = [otherBody, body];
-            otherEntity.Ticking.add(script.ticker());
+            const ticker = script.ticker();
+            ecs.addDestructionDependency(thisEntity.id, ticker);
+            ecs.addDestructionDependency(otherEntity.id, ticker);
+            otherEntity.Ticking.add(ticker);
           }
         }
         this.$$intersections.delete(other);
@@ -102,13 +108,19 @@ export default class Collider extends Component {
               const script = this.$$collisionStart.clone();
               script.context.other = otherEntity;
               script.context.pair = [body, otherBody];
-              thisEntity.Ticking.add(script.ticker());
+              const ticker = script.ticker();
+              ecs.addDestructionDependency(otherEntity.id, ticker);
+              ecs.addDestructionDependency(thisEntity.id, ticker);
+              thisEntity.Ticking.add(ticker);
             }
             if (other.$$collisionStart) {
               const script = other.$$collisionStart.clone();
               script.context.other = thisEntity;
               script.context.pair = [otherBody, body];
-              otherEntity.Ticking.add(script.ticker());
+              const ticker = script.ticker();
+              ecs.addDestructionDependency(otherEntity.id, ticker);
+              ecs.addDestructionDependency(thisEntity.id, ticker);
+              otherEntity.Ticking.add(ticker);
             }
             activeIntersections.add(intersection);
           }
diff --git a/app/ecs/components/owned.js b/app/ecs/components/owned.js
new file mode 100644
index 0000000..e10cbc5
--- /dev/null
+++ b/app/ecs/components/owned.js
@@ -0,0 +1,7 @@
+import Component from '@/ecs/component.js';
+
+export default class Owned extends Component {
+  static properties = {
+    owner: {type: 'string'},
+  };
+}
diff --git a/app/ecs/components/vulnerable.js b/app/ecs/components/vulnerable.js
new file mode 100644
index 0000000..9c0eacd
--- /dev/null
+++ b/app/ecs/components/vulnerable.js
@@ -0,0 +1,4 @@
+import Component from '@/ecs/component.js';
+
+export default class Vulnerable extends Component {
+}
diff --git a/app/server/create/homestead.js b/app/server/create/homestead.js
index 7c1b352..95be263 100644
--- a/app/server/create/homestead.js
+++ b/app/server/create/homestead.js
@@ -191,8 +191,9 @@ export default async function createHomestead(id) {
     Tags: {tags: ['kittan']},
     Ticking: {},
     VisibleAabb: {},
+    Vulnerable: {},
   };
-  for (let i = 0; i < 30; ++i) {
+  for (let i = 0; i < 10; ++i) {
     entities.push(kitty);
   }
   entities.push({
diff --git a/app/server/engine.js b/app/server/engine.js
index ad38a09..81d5ae5 100644
--- a/app/server/engine.js
+++ b/app/server/engine.js
@@ -48,6 +48,9 @@ export default class Engine {
       get frame() {
         return engine.frame;
       }
+      lookupPlayerEntity(id) {
+        return engine.lookupPlayerEntity(id);
+      }
       async readAsset(uri) {
         if (!cache.has(uri)) {
           const {promise, resolve, reject} = withResolvers();
@@ -325,6 +328,14 @@ export default class Engine {
     return player;
   }
 
+  lookupPlayerEntity(id) {
+    for (const [, player] of this.connectedPlayers) {
+      if (player.id == id) {
+        return player.entity;
+      }
+    }
+  }
+
   async saveEcs(path, ecs) {
     const view = this.Ecs.serialize(ecs);
     await this.server.writeData(path, view);
diff --git a/public/assets/magic-swords/collision-start.js b/public/assets/magic-swords/collision-start.js
new file mode 100644
index 0000000..7dee41a
--- /dev/null
+++ b/public/assets/magic-swords/collision-start.js
@@ -0,0 +1,4 @@
+const playerEntity = ecs.lookupPlayerEntity(entity.Owned.owner);
+if (playerEntity !== other && other.Vulnerable) {
+  ecs.destroy(other.id);
+}
diff --git a/public/assets/magic-swords/start.js b/public/assets/magic-swords/start.js
index 9455344..7e068ca 100644
--- a/public/assets/magic-swords/start.js
+++ b/public/assets/magic-swords/start.js
@@ -1,4 +1,4 @@
-const {Position} = wielder;
+const {Player, Position} = wielder;
 
 const shots = [];
 
@@ -23,10 +23,12 @@ for (let i = 0; i < N; ++i) {
           unstoppable: 1,
         },
       ],
+      collisionStartScript: '/assets/magic-swords/collision-start.js',
     },
     Controlled: {},
     Direction: {direction: Math.TAU * (i / N)},
     Forces: {},
+    Owned: {owner: Player ? Player.id : 0},
     Position: {x: Position.x, y: Position.y},
     Speed: {},
     Sprite: {
@@ -73,6 +75,8 @@ while (shots.length > 0) {
       shot.Direction.direction = (Math.TAU + toward) % Math.TAU;
       if (Math.distance(where, shot.Position) < 4) {
         delete accumulated[shot.id];
+        shot.Sprite.alpha = 0;
+        ecs.destroy(shot.id);
         destroying.push(shot);
       }
     }
@@ -80,8 +84,6 @@ while (shots.length > 0) {
   }
   for (let i = 0; i < destroying.length; ++i) {
     shots.splice(shots.indexOf(destroying[i]), 1);
-    destroying[i] = destroying[i].id;
   }
-  ecs.destroyMany(destroying);
-  await wait(0)
+  await wait(0);
 }