Manaborn Elemental

Magecraft — Whenever you cast or copy an
instant or sorcery spell, Put a +1/+1 counter on
Manaborn Elemental
Sacrifice Manaborn Elemental: Add X mana of
any one color, where X is Manaborn Elemental's
power. spend that mana only to cast instant or
sorcery spells.

"Born of wayward mana, it will eventually return to
it's original state."