diff --git a/common/combat/alive.trait.js b/common/combat/alive.trait.js
index b0a4ca0..b700a10 100644
--- a/common/combat/alive.trait.js
+++ b/common/combat/alive.trait.js
@@ -1,4 +1,10 @@
-import {behaviorItemFromJSON, createContext} from '@avocado/behavior';
+import {
+  behaviorItemFromJSON,
+  buildCondition,
+  buildInvoke,
+  buildTraversal,
+  createContext,
+} from '@avocado/behavior';
 import {compose} from '@avocado/core';
 import {StateProperty, Trait} from '@avocado/entity';
 
@@ -14,97 +20,30 @@ const decorate = compose(
 export class Alive extends decorate(Trait) {
 
   static defaultParams() {
+    const playDeathSound = buildInvoke(['entity', 'playSound'], [
+      buildTraversal(['entity', 'deathSound']),
+    ]);
+    const squeeze = buildInvoke(['entity', 'transition'], [
+      {
+        opacity: 0,
+        visibleScaleX: .3,
+        visibleScaleY: 3,
+      },
+      0.2,
+    ]);
+    const isLifeGone = buildCondition('<=', [
+      buildTraversal(['entity', 'life']),
+      0,
+    ]);
     return {
       deathActions: {
         type: 'actions',
         traversals: [
-          {
-            type: 'traversal',
-            steps: [
-              {
-                type: 'key',
-                key: 'entity',
-              },
-              {
-                type: 'key',
-                key: 'playSound',
-              },
-              {
-                type: 'invoke',
-                args: [
-                  {
-                    type: 'traversal',
-                    steps: [
-                      {
-                        type: 'key',
-                        key: 'entity',
-                      },
-                      {
-                        type: 'key',
-                        key: 'deathSound',
-                      },
-                    ],
-                  },
-                ],
-              },
-            ],
-          },
-          {
-            type: 'traversal',
-            steps: [
-              {
-                type: 'key',
-                key: 'entity',
-              },
-              {
-                type: 'key',
-                key: 'transition',
-              },
-              {
-                type: 'invoke',
-                args: [
-                  {
-                    type: 'literal',
-                    value: {
-                      opacity: 0,
-                      visibleScaleX: .3,
-                      visibleScaleY: 3,
-                    },
-                  },
-                  {
-                    type: 'literal',
-                    value: 0.2,
-                  },
-                ],
-              },
-            ],
-          },
-        ],
-      },
-      // By default, die when life <= 0.
-      deathCondition: {
-        type: 'condition',
-        operator: '<=',
-        operands: [
-          {
-            type: 'traversal',
-            steps: [
-              {
-                type: 'key',
-                key: 'entity',
-              },
-              {
-                type: 'key',
-                key: 'life',
-              },
-            ],
-          },
-          {
-            type: 'literal',
-            value: 0,
-          },
+          playDeathSound,
+          squeeze,
         ],
       },
+      deathCondition: isLifeGone,
       deathSound: 'deathSound',
     };
   }
diff --git a/common/combat/vulnerable.trait.js b/common/combat/vulnerable.trait.js
index e43d8c5..deb6361 100644
--- a/common/combat/vulnerable.trait.js
+++ b/common/combat/vulnerable.trait.js
@@ -1,7 +1,12 @@
 import * as I from 'immutable';
 
 import {Trait} from '@avocado/entity';
-import {behaviorItemFromJSON, createContext} from '@avocado/behavior';
+import {
+  behaviorItemFromJSON,
+  buildInvoke,
+  buildTraversal,
+  createContext,
+} from '@avocado/behavior';
 import {hasGraphics, TextNodeRenderer} from '@avocado/graphics';
 
 import {DamageEmitter} from './emitter';
@@ -9,93 +14,20 @@ import {DamageEmitter} from './emitter';
 export class Vulnerable extends Trait {
 
   static defaultParams() {
+    const emitDamage = buildInvoke(['entity', 'emitParticle'], [
+      'damage',
+      buildTraversal(['entity', 'position']),
+      buildTraversal(['damage']),
+    ]);
+    const playDamagingSound = buildInvoke(['damage', 'from', 'playSound'], [
+      buildTraversal(['damage', 'from', 'damagingSound']),
+    ]);
     return {
       tookDamageActions: {
         type: 'actions',
         traversals: [
-          {
-            type: 'traversal',
-            steps: [
-              {
-                type: 'key',
-                key: 'entity',
-              },
-              {
-                type: 'key',
-                key: 'emitParticle',
-              },
-              {
-                type: 'invoke',
-                args: [
-                  {
-                    type: 'literal',
-                    value: 'damage',
-                  },
-                  {
-                    type: 'traversal',
-                    steps: [
-                      {
-                        type: 'key',
-                        key: 'entity',
-                      },
-                      {
-                        type: 'key',
-                        key: 'position',
-                      },
-                    ],
-                  },
-                  {
-                    type: 'traversal',
-                    steps: [
-                      {
-                        type: 'key',
-                        key: 'damage',
-                      },
-                    ],
-                  },
-                ],
-              },
-            ],
-          },
-          {
-            type: 'traversal',
-            steps: [
-              {
-                type: 'key',
-                key: 'damage',
-              },
-              {
-                type: 'key',
-                key: 'from',
-              },
-              {
-                type: 'key',
-                key: 'playSound',
-              },
-              {
-                type: 'invoke',
-                args: [
-                  {
-                    type: 'traversal',
-                    steps: [
-                      {
-                        type: 'key',
-                        key: 'damage',
-                      },
-                      {
-                        type: 'key',
-                        key: 'from',
-                      },
-                      {
-                        type: 'key',
-                        key: 'damagingSound',
-                      },
-                    ],
-                  },
-                ],
-              },
-            ],
-          },
+          emitDamage,
+          playDamagingSound,
         ],
       },
     }