Arixmethes, the Slumering Isle

Arixmethes, Slumbering Isle enters the
battlefield tapped with five slumber counters
on it.
As long as Arixmethes has a slumber counter
on it, it's a land. (It's not a creature.)
Whenever you cast a spell, you may remove
a slumber counter from Arixmethes.
{t}:Add {g}{u}