diff --git a/dungeonbattle/entities/monsters.py b/dungeonbattle/entities/monsters.py
index 2246e50..7c19c62 100644
--- a/dungeonbattle/entities/monsters.py
+++ b/dungeonbattle/entities/monsters.py
@@ -1,9 +1,19 @@
+from random import choice
+
 from ..interfaces import FightingEntity, Map
 
 
 class Monster(FightingEntity):
     def act(self, m: Map) -> None:
-        pass
+        """
+        By default, a monster will move randomly where it is possible
+        And if a player is close to the monster, the monster run on the player.
+        """
+        # TODO If a player is close, move to the player
+        while True:
+            if choice([self.move_up, self.move_down,
+                      self.move_left, self.move_right])():
+                break
 
 
 class Hedgehog(Monster):
diff --git a/dungeonbattle/game.py b/dungeonbattle/game.py
index 23cc598..e8f412c 100644
--- a/dungeonbattle/game.py
+++ b/dungeonbattle/game.py
@@ -71,6 +71,7 @@ class Game:
             self.display_refresh()
             key = screen.getkey()
             self.handle_key_pressed(self.translate_key(key))
+            self.map.tick()
 
     def translate_key(self, key: str) -> KeyValues:
         """
diff --git a/dungeonbattle/interfaces.py b/dungeonbattle/interfaces.py
index 4c281e4..65e381d 100644
--- a/dungeonbattle/interfaces.py
+++ b/dungeonbattle/interfaces.py
@@ -88,6 +88,13 @@ class Map:
             hedgehog.move(y, x)
             self.add_entity(hedgehog)
 
+    def tick(self) -> None:
+        """
+        Trigger all entity events.
+        """
+        for entity in self.entities:
+            entity.act(self)
+
 
 class Tile(Enum):
     EMPTY = auto()