Trell, Hidden Marshlands

Trell, Hidden Marshlands enters the battlefield tapped unless you control four or more lands.
{t}: Add {b}{g} or {g}{u} or {u}{b} to your mana pool.
If you venture out at night
You better be careful of where you do romp
Out in this swamp where the tree moss hangs thick
You better step lively you better step quick
--Swamp Creature, by Pauline Russell