diff --git a/app/ecs-components/collider.js b/app/ecs-components/collider.js
new file mode 100644
index 0000000..f55de3a
--- /dev/null
+++ b/app/ecs-components/collider.js
@@ -0,0 +1,75 @@
+import Component from '@/ecs/component.js';
+import {intersects} from '@/util/math.js';
+
+import vector2d from './helpers/vector-2d';
+
+export default class Collider extends Component {
+  instanceFromSchema() {
+    const {ecs} = this;
+    return class ColliderInstance extends super.instanceFromSchema() {
+      isCollidingWith(other) {
+        const {aabb, aabbs} = this;
+        const {aabb: otherAabb, aabbs: otherAabbs} = other;
+        if (!intersects(aabb, otherAabb)) {
+          return false;
+        }
+        for (const aabb of aabbs) {
+          for (const otherAabb of otherAabbs) {
+            if (intersects(aabb, otherAabb)) {
+              return true;
+            }
+          }
+        }
+        return false;
+      }
+      isWithin(query) {
+        const {aabb, aabbs} = this;
+        if (!intersects(aabb, query)) {
+          return false;
+        }
+        for (const aabb of aabbs) {
+          if (intersects(aabb, query)) {
+            return true;
+          }
+        }
+        return false;
+      }
+      recalculateAabbs() {
+        const {Position: {x: px, y: py}} = ecs.get(this.entity);
+        this.aabb = {x0: Infinity, x1: -Infinity, y0: Infinity, y1: -Infinity};
+        this.aabbs = [];
+        const {bodies} = this;
+        for (const points of bodies) {
+          let x0 = Infinity, x1 = -Infinity, y0 = Infinity, y1 = -Infinity;
+          for (const point of points) {
+            const x = point.x + px;
+            const y = point.y + py;
+            if (x < x0) x0 = x;
+            if (x < this.aabb.x0) this.aabb.x0 = x;
+            if (x > x1) x1 = x;
+            if (x > this.aabb.x1) this.aabb.x1 = x;
+            if (y < y0) y0 = y;
+            if (y < this.aabb.y0) this.aabb.y0 = y;
+            if (y > y1) y1 = y;
+            if (y > this.aabb.y1) this.aabb.y1 = y;
+          }
+          this.aabbs.push({
+            x0: x0 > x1 ? x1 : x0,
+            x1: x0 > x1 ? x0 : x1,
+            y0: y0 > y1 ? y1 : y0,
+            y1: y0 > y1 ? y0 : y1,
+          });
+        }
+      }
+    }
+  }
+  static properties = {
+    bodies: {
+      type: 'array',
+      subtype: {
+        type: 'array',
+        subtype: vector2d('int16'),
+      },
+    },
+  };
+}
diff --git a/app/ecs-systems/colliders.js b/app/ecs-systems/colliders.js
new file mode 100644
index 0000000..1cf52e0
--- /dev/null
+++ b/app/ecs-systems/colliders.js
@@ -0,0 +1,90 @@
+import {System} from '@/ecs/index.js';
+import SpatialHash from '@/util/spatial-hash.js';
+
+export default class Colliders extends System {
+
+  hash;
+
+  deindex(entities) {
+    super.deindex(entities);
+    for (const id of entities) {
+      this.hash.remove(id);
+    }
+  }
+
+  static get priority() {
+    return {
+      after: 'IntegratePhysics',
+    };
+  }
+
+  reindex(entities) {
+    for (const id of entities) {
+      if (1 === id) {
+        this.hash = new SpatialHash(this.ecs.get(1).AreaSize);
+      }
+    }
+    super.reindex(entities);
+    for (const id of entities) {
+      this.updateHash(this.ecs.get(id));
+    }
+  }
+
+  updateHash(entity) {
+    if (!entity.Collider) {
+      return;
+    }
+    entity.Collider.recalculateAabbs();
+    this.hash.update(entity.Collider.aabb, entity.id);
+  }
+
+  tick() {
+    const seen = {};
+    for (const entity of this.ecs.changed(['Position'])) {
+      if (seen[entity.id]) {
+        continue;
+      }
+      seen[entity.id] = true;
+      if (!entity.Collider) {
+        continue;
+      }
+      this.updateHash(entity);
+      for (const other of this.within(entity.Collider.aabb)) {
+        if (seen[other.id]) {
+          continue;
+        }
+        seen[other.id] = true;
+        if (!other.Collider) {
+          continue;
+        }
+        if (entity.Collider.isCollidingWith(other.Collider)) {
+          console.log('collide', entity, other);
+        }
+      }
+    }
+  }
+
+  within(query) {
+    const {x0, x1, y0, y1} = query;
+    const [cx0, cy0] = this.hash.chunkIndex(x0, y0);
+    const [cx1, cy1] = this.hash.chunkIndex(x1, y1);
+    const seen = {};
+    const within = new Set();
+    for (let cy = cy0; cy <= cy1; ++cy) {
+      for (let cx = cx0; cx <= cx1; ++cx) {
+        for (const id of this.hash.chunks[cx][cy]) {
+          if (seen[id]) {
+            continue;
+          }
+          seen[id] = true;
+          const entity = this.ecs.get(id);
+          if (entity.Collider.isWithin(query)) {
+            within.add(entity);
+          }
+        }
+      }
+    }
+    return within;
+  }
+
+}
diff --git a/app/engine.js b/app/engine.js
index 63483b4..b372d75 100644
--- a/app/engine.js
+++ b/app/engine.js
@@ -167,6 +167,7 @@ export default class Engine {
       'PlantGrowth',
       'FollowCamera',
       'VisibleAabbs',
+      'Collliders',
       'ControlDirection',
       'SpriteDirection',
       'RunAnimations',
diff --git a/app/util/math.js b/app/util/math.js
index 51fc013..1d20762 100644
--- a/app/util/math.js
+++ b/app/util/math.js
@@ -1,3 +1,9 @@
+export function distance({x: lx, y: ly}, {x: rx, y: ry}) {
+  const xd = lx - rx;
+  const yd = ly - ry;
+  return Math.sqrt(xd * xd + yd * yd);
+}
+
 export function intersects(l, r) {
   if (l.x0 > r.x1) return false;
   if (l.y0 > r.y1) return false;
diff --git a/public/assets/tomato-seeds/start.js b/public/assets/tomato-seeds/start.js
index 0b5d511..804d2a2 100644
--- a/public/assets/tomato-seeds/start.js
+++ b/public/assets/tomato-seeds/start.js
@@ -9,6 +9,16 @@ if (projected?.length > 0) {
   const [, direction] = Sprite.animation.split(':')
 
   const plant = {
+    Collider: {
+      bodies: [
+        [
+          {x: -8, y: -8},
+          {x: 8, y: -8},
+          {x: -8, y: 8},
+          {x: 8, y: 8},
+        ],
+      ],
+    },
     Interactive: {
       interactScript: '/assets/tomato-plant/interact.js',
     },