diff --git a/image/card/delayedTrick/unknown.png b/image/card/delayedTrick/unknown.png
index 0c0f0c3704ed05b834a4f061a1287b0bc6661a0d..4731fd9b19703fbeb9b43be72bf4c75be56f164c 100644
Binary files a/image/card/delayedTrick/unknown.png and b/image/card/delayedTrick/unknown.png differ
diff --git a/lua/server/ai/random_ai.lua b/lua/server/ai/random_ai.lua
index cfb12ac9342c60c7fd3aaaa578098604a3b7c903..6a5ca098476ba49a7c082b3bf72b400732298140 100644
--- a/lua/server/ai/random_ai.lua
+++ b/lua/server/ai/random_ai.lua
@@ -10,6 +10,8 @@ function RandomAI:useActiveSkill(skill, card)
   local room = self.room
   local player = self.player
 
+  if skill:isInstanceOf(ViewAsSkill) then return "" end
+
   local filter_func = skill.cardFilter
   if card then
     filter_func = Util.FalseFunc
@@ -68,6 +70,7 @@ function RandomAI:useVSSkill(skill, pattern, cancelable, extra_data)
   local player = self.player
   local room = self.room
   local precondition
+  if not skill then return nil end
 
   if self.command == "PlayCard" then
     precondition = skill:enabledAtPlay(player)