Spirit of Time

{u}: Spirit of Time becomes a 2/2 wizard spirit.
{u}{u}: If Spirit of Time is a spirit, it becomes a
4/4 wizard spirit warrior.
{u}{u}{u}{u}: If Spirit of Time is a warrior, it
becomes a 6/6 wizard spirit warrior avatar with
flying and: whenever you cast an instant or
sorcery spell, put a +1+1 counter on Spirit of
Time.