Ghazghkull, Frenzied Prophet

Trample, Double Strike
Ghaghkull, Frenzied Prophet costs {x} less to cast
where X is the amount of life your opponents lost
this turn.
Vehicles you control have a crew cost of 2
{b}{b}: Sacrifice {x} target creatures you control.
Return an Artifact from your graveyard to the battlefield that costs {x} or less.