diff --git a/src/core/Global.ttslua b/src/core/Global.ttslua
index fe90e66d..2ca9fdd2 100644
--- a/src/core/Global.ttslua
+++ b/src/core/Global.ttslua
@@ -185,6 +185,11 @@ end
 -- This requires the try method as cards won't exist any more after they enter a deck, so the lines
 -- can't be cleared.
 function tryObjectEnterContainer(container, object)
+  -- stop mini cards from forming decks
+  if object.hasTag("Minicard") and container.hasTag("Minicard") then
+    return false
+  end
+
   playAreaApi.tryObjectEnterContainer(container, object)
   return true
 end