Cave Hydra

Double Attack
Cave Hydra gets a +1,+1 for every extra mana
used when casting.
Cave Hydra can {t}{5}{p/w}{p/u}{p/b}{p/r}{p/g}{p/c} to reenter
your deck face up, with a shuffle, when it
becomes the top card the base 15 used to cast
doesn't need re-spent, but the X may be respent
to add more +1, +1s onto Cave hydra, but it loses
all from before this effect.