diff --git a/assets.h b/assets.h
index 558ea07..508d28a 100644
--- a/assets.h
+++ b/assets.h
@@ -493,6 +493,27 @@ SFG_PROGRAM_MEMORY uint8_t SFG_monsterSprites[][SFG_TEXTURE_STORE_SIZE] =
 5,185,172,16,0,0,0,2,38,136,134,34,80,80,0,0,0,88,167,65,0,0,0,0,182,136,134,98,
 80,0,0,0,0,5,185,145,17,17,16,0,34,102,102,102,32,0,0,0,0,0,87,153,52,51,49,0,2,
 98,34,102,107,0,0,0,0,0,1,116,71,65,16,0,2,37,82,43,32,0,0,0,0,0,0,17,17,16,0
+  },
+  { // 2, spider walking
+175,0,4,5,6,3,223,1,10,7,2,18,62,95,120,63,0,0,17,17,0,0,0,0,0,0,0,1,17,17,0,0,
+0,1,50,211,16,0,0,0,0,0,0,21,51,50,16,0,0,19,26,161,49,0,0,0,0,0,17,146,35,33,0,
+0,0,29,173,90,33,0,0,0,0,1,148,68,81,16,0,0,0,18,165,218,209,0,16,0,0,25,67,49,
+16,0,0,0,0,19,26,161,49,16,17,0,1,148,51,16,0,0,0,0,0,1,61,35,119,113,84,16,25,
+68,56,0,0,0,0,0,0,23,81,23,87,83,51,16,17,21,129,0,0,0,0,0,1,50,55,114,130,67,
+68,65,0,1,50,16,0,0,0,0,1,37,39,81,68,67,51,50,0,1,85,81,17,17,17,0,1,50,215,17,
+204,67,35,35,16,25,153,148,68,83,50,16,0,17,18,68,111,108,50,34,16,1,68,68,68,
+82,37,81,0,1,68,67,105,246,98,34,33,0,133,88,136,136,136,129,0,1,23,117,198,150,
+102,34,34,238,227,37,181,17,0,0,0,21,135,87,82,102,252,98,46,123,91,50,81,0,0,0,
+1,37,24,136,114,38,159,101,235,181,35,181,112,0,0,0,1,37,24,136,114,38,159,101,
+235,181,35,181,112,0,0,0,0,21,135,87,82,102,252,98,46,123,83,123,33,0,0,0,0,1,
+23,117,198,150,102,34,34,238,235,50,133,17,17,0,0,1,68,67,105,246,98,34,33,0,
+131,40,85,85,34,16,0,17,18,68,111,108,50,34,16,1,148,33,17,17,17,0,1,50,215,17,
+204,67,35,35,16,25,50,16,0,0,0,0,1,37,39,81,68,67,51,50,17,148,72,136,128,0,0,0,
+1,50,55,114,130,67,68,65,20,68,73,148,136,128,0,0,0,23,81,23,87,83,51,16,1,17,
+84,68,83,56,129,0,0,1,61,35,119,113,84,16,0,5,21,68,82,34,81,0,0,19,26,161,49,
+16,17,0,0,20,66,87,18,37,16,0,0,18,165,218,209,0,16,0,0,1,84,52,65,17,81,17,0,
+29,173,90,33,0,0,0,0,0,17,19,52,82,37,16,0,19,26,161,49,0,0,0,0,0,0,1,19,82,81,
+0,0,1,50,211,16,0,0,0,0,0,0,0,1,17,16,0,0,0,17,17,0,0,0,0,0,0,0,0,0,0,0,0
   }
 };
 
diff --git a/constants.h b/constants.h
index 2fc83e0..4bc5c3a 100644
--- a/constants.h
+++ b/constants.h
@@ -58,13 +58,13 @@
   Rate at which AI will be updated, which also affects how fast enemies will
   appear.
 */
-#define SFG_AI_FPS 2
+#define SFG_AI_FPS 4
 
 /**
   Says a probability (0 - 255) of the AI changing its state during one update
   step.
 */
-#define SFG_AI_RANDOM_CHANGE_PROBABILITY 20
+#define SFG_AI_RANDOM_CHANGE_PROBABILITY 40
 
 /**
   Speed of rocket projectile, in squares per second.
diff --git a/main.c b/main.c
index 587618f..b89048a 100755
--- a/main.c
+++ b/main.c
@@ -329,6 +329,13 @@ typedef struct
   #define SFG_EXPLOSION_DURATION_FRAMES 1
 #endif
 
+#define SFG_SPRITE_ANIMATION_FRAME_DURATION \
+  (SFG_FPS / SFG_SPRITE_ANIMATION_SPEED)
+
+#if SFG_SPRITE_ANIMATION_FRAME_DURATION == 0
+  #define SFG_SPRITE_ANIMATION_FRAME_DURATION 1
+#endif
+
 /*
   GLOBAL VARIABLES
 ===============================================================================
@@ -336,6 +343,8 @@ typedef struct
 
 uint8_t SFG_currentRandom;
 
+uint8_t SFG_spriteAnimationFrame;
+
 struct
 {
   RCL_Camera camera;
@@ -1018,6 +1027,8 @@ void SFG_setAndInitLevel(const SFG_Level *level)
 
   SFG_currentLevel.timeStart = SFG_getTimeMs(); 
   SFG_currentLevel.frameStart = SFG_gameFrame;
+
+  SFG_spriteAnimationFrame = 0;
  
   SFG_initPlayer();
 }
@@ -1068,9 +1079,10 @@ void SFG_monsterPerformAI(SFG_MonsterRecord *monster)
   if (SFG_random() < SFG_AI_RANDOM_CHANGE_PROBABILITY)
   { 
     // sometimes randomly change state
-    state = SFG_MONSTER_STATE_IDLE;
+    state = (SFG_random() % 4 == 0) ?
+      SFG_MONSTER_STATE_IDLE : SFG_MONSTER_STATE_ATTACKING;
   }
-  if (state == SFG_MONSTER_STATE_IDLE)
+  else if (state == SFG_MONSTER_STATE_IDLE)
   {
     switch (SFG_random() % 8)
     {
@@ -1085,6 +1097,10 @@ void SFG_monsterPerformAI(SFG_MonsterRecord *monster)
       default: break;
     }
   }
+  else if (state == SFG_MONSTER_STATE_ATTACKING)
+  {
+    state = SFG_MONSTER_STATE_IDLE;
+  }
   else
   {
     if (state == SFG_MONSTER_STATE_GOING_E ||
@@ -1323,6 +1339,10 @@ void SFG_gameStep()
   for (uint8_t i = 0; i < SFG_KEY_COUNT; ++i)
     SFG_keyStates[i] = (SFG_keyStates[i] << 1) | SFG_keyPressed(i);
 
+  if ((SFG_currentLevel.frameStart - SFG_gameFrame) %
+      SFG_SPRITE_ANIMATION_FRAME_DURATION == 0)
+    SFG_spriteAnimationFrame++;
+
   int8_t recomputeDirection = 0;
 
   RCL_Vector2D moveOffset;
@@ -2052,7 +2072,9 @@ void SFG_draw()
     {
       SFG_MonsterRecord m = SFG_currentLevel.monsterRecords[i];
 
-      if (m.stateType != SFG_MONSTER_STATE_INACTIVE)
+      uint8_t state = m.stateType & SFG_MONSTER_MASK_STATE;
+
+      if (state != SFG_MONSTER_STATE_INACTIVE)
       {
         RCL_Vector2D worldPosition;
 
@@ -2069,10 +2091,21 @@ void SFG_draw()
             SFG_player.camera);
 
         if (p.depth > 0)
-          SFG_drawScaledSprite(SFG_monsterSprites[ (SFG_gameFrame >> 5) & 0x01 ],
+        {
+          const uint8_t *s;
+
+          if (state == SFG_MONSTER_STATE_IDLE)
+            s = SFG_monsterSprites[0];
+          else if (state == SFG_MONSTER_STATE_ATTACKING)
+            s = SFG_monsterSprites[1];
+          else
+            s = SFG_monsterSprites[SFG_spriteAnimationFrame & 0x01 ? 0 : 2];
+
+          SFG_drawScaledSprite(s,
             p.position.x * SFG_RAYCASTING_SUBSAMPLE,p.position.y,
             RCL_perspectiveScale(SFG_GAME_RESOLUTION_Y,p.depth),
             p.depth / (RCL_UNITS_PER_SQUARE * 2),p.depth);
+        }
       }
     }
 
diff --git a/settings.h b/settings.h
index 9dca7ed..6f7c22b 100644
--- a/settings.h
+++ b/settings.h
@@ -130,4 +130,9 @@
 */
 #define SFG_EXPLOSION_DURATION 70
 
+/**
+  Specifies how quick some sprite animations are, in frames per second.
+*/
+#define SFG_SPRITE_ANIMATION_SPEED 4
+
 #endif // guard