Prozen, Saurer's Genesis

Whenever another non-human creature enters
the battlefield under your control it becomes an
artifact vehicle with Crew 1 and "Whenever a
human crews this vehicle it get's +X/+Y, where
X is the crewing creature's power and Y is its
toughness."
{t}, Sacrifice Prozen, Saurer's Genesis: Each non artifact creature gets -X/-X where X is the power
of a crewed vehicle you control.