Henry Knox

As long as you control an artifact creature with
power 4 or greater, Henry Knox has hexproof.
When Henry Knox enters the battlefield, create
X 4/2 colorless Cannon artifact creature token
with trample.
Sacrifice two creatures with power 4 or greater,
{2}{w}{w}, {t}: Search your library for an artifact
card and put it onto the battlefield untapped.
All artifact creatures you control gain trample
and haste until end of turn.