Venusaur

Level Up {2}{g}{g}
LEVEL 1-2 4/5, Giga Drain {g}{g}{t}: deal 4 damage to each permanent, you gain life equal to the damage
LEVEL 3-5 4/6, Giga Drain, Synthesize {g}{t}: add {g} for each nonswamp and nonmountain
land on the field. This mana doesnt empty from
your mana pool as long Venusaur is on the field.
LEVEL 6+ 5/7, Giga Drain, Synthesize, Solar Beam {3}{g}{g}{t}: deal X damage to any target equal to the amount of mana in your mana pool. Venusaur
doesn't untap during your next untap step.