Diaphoros, Master of Forms

Diaphoros's power and toughness are equal to the number of creature types among permanents on the battlefield.
{u}{t}: Target creature loses all abilities and becomes a 0/2 changeling until end of turn.
{u}{u}{u}: Monstrosity X, where X is the number of creature types among permanents on the battlefield.
Remove a +1/+1 counter from Diaphoros: Creatures of a chosen type cannot target or deal damage to him until end of turn.