Ivysaur

{1}{t}: Ivysaur deals 1 damage to target creature
and tap it; and it does not untap during its
controller's next untap step.
At the beginning of your End Phase, if you
control six or more lands; you may sacrifice
Ivysaur. If you do, search your hand and library
for a card named Venusaur, and place it in the battlefield. Shuffle your library afterwards.