Stensia

Oracle Text

Whenever a creature deals damage to one or more players for the first time each turn, put a +1/+1 counter on it.

Whenever you roll H, each creature you control gains "T: This creature deals 1 damage to target player or planeswalker" until end of turn.

Card Rulings

6/1/2012 Each creature can have only one +1/+1 counter put on it this way per turn.
6/1/2012 Unlike the Vampires in the _Innistrad_(TM) block, Stensia’s ability triggers whenever a creature deals any damage, not just combat damage.