Grubskup

Haste
This creature must attack each combat if able.
When Grubskup attacks, target opponent reveals
cards from the top of their library until they
reveal an instant or sorcery, exile it, then shuffle.
You may cast that spell this turn without paying
its mana cost. Grubskup gets +X/+X until end
of turn where X is that spells converted
mana cost.