Fire items and Dragons Ruling

hi there,



here's the situation:



We're playing munchkin.



It's my turn and kicking down the door I find the Plutonium Dragon ( and we are using the dragon rules ).

So, it's immune to fire/flame items BUT my big ones count double.



player B play "BookWyrm" on me cause it's a Dragon too, but now also my fire/flame items count double against them altogether.



then player C play Smog on me and here is my question: because of the entrance of Smog wich is a regular dragon, the fire/flame immunity is now restored cause it's the last monster who joined the fight OR the bookworm effect is still active and all my fire/flame and big items count double altogether?



thanks in advance

Fire items and Dragons Ruling