Creature - Vampire 3/4, 4BB (6) Flying Each creature you control is a Vampire in addition to its other creature types and has "Whenever this creature deals damage to a creature, put a +1/+1 counter on this creature."1
Illus. Matthew D. Wilson
If you control two of these, then every one of your creatures has two copies of the ability and will get two counters when it deals damage. [D'Angelo 2007/06/04]