The Vault Cultivator

Begin the game with this card revealed.
Only creatures you control gain defender, and
"during your upkeep, put a age counter on
this card. When this card has six age counters,
remove all six, and this card gets four +1/+1
counters, loses defender, gains haste and
reach."
You can only attack if you were attacked,
and you lose twice as much life from effect
damage or "lose life" effects.