Trealex, Envoy of Onslaught

Artifact creatures you control get +1/+1 for
each time you've cast Trealex, Envoy of
Onslaught this game.
When a crewed vehicle you control is sent from
the field to the graveyard, it deals damage equal
to its power to any target.
{t}: Crew Target vehicle. Activate this ability
only once per turn.