Weaken

 is an active ability, which means it will only activate once the creature has a full bloodlust counter.  For a list of all Cards with this ability, click here! 

Variations
can appear as certain activation, or with a chance to activate. It always activates during the card's turn. It can target the opposing, one, several or all enemy creatures, and it may target only a specific race. The decrease amount is usually 1 or 2, in rare cases 3.