Inf life, damage and huge creatures

Pay 3 life: Put a +1/+1 counter on target creature.

You don't lose the game for having 0 or less life. When you have 20 or more life, you lose the game. Whenever you lose life, you gain 2 life for each 1 life you lost. (Damage dealt to you causes you to lose life.)

Flying This creature enters with a +1/+1 counter on it. , Remove a +1/+1 counter from this creature: Destroy target enchantment.

This creature enters with three +1/+1 counters on it. Remove a +1/+1 counter from this creature: It deals 1 damage to any target.