Eolys, Hydra Tamer

Whenever you cast a spell with {x} in its mana
cost, choose one that hasn't been chosen —
• Target creature you control gets +X/+X until
end of turn.
• Tap up to X target creatures.
• Eolys, Hydra Tamer deals X damage to target creature or planeswalker.
{bull} Eolys, Hydra Tamer becomes a legendary X/X
Hydra creature and loses all other types and
abilities.