MArcomage

enemy played basilisk and after that i only had 5 wall left.
this should be impossible since basilisk gives both players 10 wall after the attack.

screenshot (something is wrong with the picture, but you can see what is important):
http://i222.photobucket.com/albums/dd184/insektenplage/BasiliskBug.jpg

Beast - there is a 8% chance for each Beast card in hand (not counting the played one) that additional damage will be inflicted upon your enemy based on played card rarity (Common - 2 , Uncommon - 5, Rare - 10).

I bet your opponent has other Beast cards in hand?

Yes, this is it - Beast side effect was activated, thus lowering your wall by 5. (it happened after card effect).

ah, didn't know that the effect is triggered after the card.

thanks