diff --git a/app/react/components/devtools/entities.jsx b/app/react/components/devtools/entities.jsx
new file mode 100644
index 0000000..8c88248
--- /dev/null
+++ b/app/react/components/devtools/entities.jsx
@@ -0,0 +1,172 @@
+import {Map} from 'immutable';
+import {useCallback, useEffect, useState} from 'react';
+
+import {useClient} from '@/react/context/client.js';
+import {useEcs, useEcsTick} from '@/react/context/ecs.js';
+
+import styles from './entities.module.css';
+
+const entityJsonPaths = Object.keys(import.meta.glob('%/**/*.entity.json'));
+
+function entityLabel(entity) {
+  let label = `${entity.id}`;
+  const {Player, Position} = entity;
+  if (1 === entity.id) {
+    label = 'Master';
+  }
+  if (Player) {
+    label += `: Player (${Player.id})`;
+  }
+  if (Position) {
+    label += `: [${Position.x.toFixed(2)}, ${Position.y.toFixed(2)}]`
+  }
+  return label;
+}
+
+function Entities({eventsChannel}) {
+  const client = useClient();
+  const ecsRef = useEcs();
+  const [activeEntity, setActiveEntity] = useState(1);
+  const [creatingEntityPath, setCreatingEntityPath] = useState(entityJsonPaths[0]);
+  const [entities, setEntities] = useState(Map());
+  const onEcsTick = useCallback((payload, ecs) => {
+    setEntities((entities) => {
+      return entities.withMutations((entities) => {
+        if (0 === entities.size) {
+          for (const id in ecs.$$entities) {
+            const entity = ecs.get(id);
+            entities.set(id, entityLabel(entity));
+          }
+          return;
+        }
+        for (const id in payload) {
+          const update = payload[id];
+          if (false === update) {
+            entities.delete(id);
+          }
+          else {
+            const entity = ecs.get(id);
+            entities.set(id, entityLabel(entity));
+          }
+        }
+      });
+    });
+  }, []);
+  useEcsTick(onEcsTick);
+  useEffect(() => {
+    if (!ecsRef.current) {
+      return;
+    }
+    const master = ecsRef.current.get(1);
+    if (!master) {
+      return;
+    }
+    const {TileLayers} = master;
+    const {size, tileSize} = TileLayers.layer(0);
+    function onClick({x, y}, {shiftKey}) {
+      const at = {
+        x: shiftKey ? Math.floor(x / tileSize.x) * tileSize.x + (tileSize.x / 2) : x,
+        y: shiftKey ? Math.floor(y / tileSize.y) * tileSize.y + (tileSize.y / 2) : y,
+      };
+      if (at.x < 0 || at.y < 0 || at.x >= size.x || at.y >= size.y) {
+        return;
+      }
+      const entity = ecsRef.current.get(activeEntity);
+      if (!entity.Position) {
+        return;
+      }
+      client.send({
+        type: 'AdminAction',
+        payload: {
+          type: 'moveEntity',
+          value: {
+            id: activeEntity,
+            at,
+          },
+        },
+      });
+    }
+    eventsChannel.addListener('click', onClick);
+    return () => {
+      eventsChannel.removeListener('click', onClick);
+    };
+  }, [activeEntity, client, ecsRef, eventsChannel]);
+  const options = [];
+  for (const [id, label] of entities.entries()) {
+    options.push(
+      <option
+        key={id}
+        value={id}
+      >
+        {label}
+      </option>);
+  }
+  return (
+    <div className={styles.entities}>
+      <form>
+        <div
+          className={styles.activeEntity}
+        >
+          <button
+            onClick={(event) => {
+              client.send({
+                type: 'AdminAction',
+                payload: {
+                  type: 'destroyEntity',
+                  value: {
+                    id: activeEntity,
+                  },
+                },
+              });
+              event.preventDefault();
+            }}
+          >
+            -
+          </button>
+          <select
+            onChange={(event) => {
+              setActiveEntity(event.target.value);
+            }}
+            value={activeEntity}
+          >
+            {options}
+          </select>
+        </div>
+        <div
+          className={styles.createEntity}
+        >
+          <button
+            onClick={(event) => {
+              client.send({
+                type: 'AdminAction',
+                payload: {
+                  type: 'createEntity',
+                  value: {
+                    path: creatingEntityPath,
+                  },
+                },
+              });
+              event.preventDefault();
+            }}
+          >
+            +
+          </button>
+          <select
+            onChange={(event) => {
+              setCreatingEntityPath(event.target.value);
+            }}
+            value={creatingEntityPath}
+          >
+            {entityJsonPaths.map((path) => (
+              <option key={path} value={path}>{path}</option>
+            ))}
+          </select>
+        </div>
+      </form>
+    </div>
+  );
+}
+
+Entities.displayName = 'Entities';
+
+export default Entities;
diff --git a/app/react/components/devtools/entities.module.css b/app/react/components/devtools/entities.module.css
new file mode 100644
index 0000000..c62fbed
--- /dev/null
+++ b/app/react/components/devtools/entities.module.css
@@ -0,0 +1,7 @@
+.activeEntity {
+  display: flex;
+}
+
+.createEntity {
+  display: flex;
+}
diff --git a/app/silphius/server/engine.js b/app/silphius/server/engine.js
index afaaf7e..6b107c9 100644
--- a/app/silphius/server/engine.js
+++ b/app/silphius/server/engine.js
@@ -195,6 +195,16 @@ export default class Engine {
             });
             break;
           }
+          case 'createEntity': {
+            const {path} = payload.value;
+            ecs.create({$$extends: path});
+            break;
+          }
+          case 'destroyEntity': {
+            const {id} = payload.value;
+            ecs.destroy(parseInt(id));
+            break;
+          }
           case 'paint': {
             const {TileLayers} = ecs.get(1);
             const {brush, layer: paintLayer, stamp} = payload.value;
@@ -213,6 +223,15 @@ export default class Engine {
             }
             break;
           }
+          case 'moveEntity': {
+            const {at: {x, y}, id} = payload.value;
+            const entity = ecs.get(id);
+            if (entity.Position) {
+              entity.Position.x = x;
+              entity.Position.y = y;
+            }
+            break;
+          }
           case 'moveUp':
           case 'moveRight':
           case 'moveDown':
diff --git a/package-lock.json b/package-lock.json
index 6c8bcd8..cbc1097 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -26,6 +26,7 @@
         "cross-env": "^7.0.3",
         "express": "^4.19.2",
         "idb-keyval": "^6.2.1",
+        "immutable": "^5.0.2",
         "isbot": "^4.1.0",
         "kefir": "^3.8.8",
         "morgan": "^1.10.0",
@@ -36,7 +37,7 @@
         "remark-mdx": "^3.0.1",
         "remark-parse": "^11.0.0",
         "simplex-noise": "^4.0.1",
-        "sylvite": "^1.0.5",
+        "sylvite": "^1.0.6",
         "unified": "^11.0.5",
         "unist-util-visit-parents": "^6.0.1",
         "ws": "^8.18.0"
@@ -11571,6 +11572,11 @@
         "node": ">=16.x"
       }
     },
+    "node_modules/immutable": {
+      "version": "5.0.2",
+      "resolved": "https://registry.npmjs.org/immutable/-/immutable-5.0.2.tgz",
+      "integrity": "sha512-1NU7hWZDkV7hJ4PJ9dur9gTNQ4ePNPN4k9/0YhwjzykTi/+3Q5pF93YU5QoVj8BuOnhLgaY8gs0U2pj4kSYVcw=="
+    },
     "node_modules/import-fresh": {
       "version": "3.3.0",
       "resolved": "https://registry.npmjs.org/import-fresh/-/import-fresh-3.3.0.tgz",
diff --git a/package.json b/package.json
index 0736bee..5b6abbb 100644
--- a/package.json
+++ b/package.json
@@ -32,6 +32,7 @@
     "cross-env": "^7.0.3",
     "express": "^4.19.2",
     "idb-keyval": "^6.2.1",
+    "immutable": "^5.0.2",
     "isbot": "^4.1.0",
     "kefir": "^3.8.8",
     "morgan": "^1.10.0",