Raging Mana Serpent

When Raging Mana Serpent enters the battlefield, you may pay one {u} mana to add a +1/+1 counter onto it, do this as many times as
you like.
{r}{r}: Raging Mana Serpent has First Strike until your next turn. While it has First Strike
and if it does go into the graveyard, deal two damage to target creature.