Gnome Wizard Graveyard

Magecraft — Whenever you cast or copy an
instant sorcery spell you may exile a creature
card from a graveyard with mana cost X or less
where X is equal to the spells mana cost.
Until end of turn you may have up to X target
nonland permanents become a copy of the exiled creature.
The copies are 2/2 green Frogs and have
"Pay 2 life: Return this creature back to normal.
This ability can be activated by your opponents."