Grolbixis, Ally of Kings

Flying, firststrike
Rally — Whenever Grolbixis, Ally of Kings, or another Ally enters the battlefield under you
control. Creatures you control get +3/+3 and
gain trample until end of turn.
"Once a general of Jaarl-Khan's army, now he is a
close ally to King Tiberius, and, Queen Myar."
— Tome of Ancient Wars, Verse 2305