Prophecy Remade

(You may cast a legendary instant only if you control
a legendary creature or planeswalker.)
This spell costs {4} less to cast if an opponent has
their commander on the battlefield.
Creatures you control gain trample and indestructible until end of turn. Put X
+1/+1 counters on target creature you control,
where X is the number of legendary permanents
on the battlefield.