Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever Stronghold Rats deals combat damage to a player, each player discards a card.
First the active player chooses a card to discard, then each other player in turn order chooses, then all cards are discarded simultaneously. Although the chosen cards will be indicated (so a player can’t change their mind later), they’ll remain face down until they’re discarded. You won’t know what your opponent is going to discard when making your choice.