Reincarnate

Enchant creature
Enchanted creature has "When this creature dies,
you may search your library for a creature card
with a lesser converted mana cost, put that card
onto the battlefield, then shuffle your library."
When Reincarnate is put into your graveyard
from the battlefield, you may pay {4}{g}{g}. If you
do, return it to the battlefield enchanting target creature you control.