Mana Chemist

Study - {1}{g}, Exile a creature you control. (For
each creature you control that shares a creature type
with the exiled card, put a study counter on this.)
{x}, {t}, Remove a study counter from Mana
Chemist: Add X mana in any combination of
colors. Activate this ability only once each turn.
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"For some, mana is life. For me, it's an ingredient."