Caleb, Wizard Supreme

You may choose to not to untap Caleb, Wizard Supreme during your untap step.
{t}: deal 2 damage.
{2}{r}{t}: target creature gains +0/+2 and double strike as long as Caleb is tapped.
{2}{b}{b}{b}{t}: Target creature loses indestructible. Deal 6 damage to it.
{u}{u}{t}: Counter Target Ability.