Tetranadon Armor

Equip {x}{2}
Equiped creature gets +X/+X, it looses this bonus if it has taken damage since it was equiped.
Tap a land, it does not untap on your next untap step: Put a +1/+1 counter on equiped creature, activate this only once each round.
When equiped creature takes damage
remove a +1/+1 counter from it.