Ggorulluzg, the Lurker

at the beginning of your upkeep, you may pay
{b}{g}, if you don't, shuffle Ggorulluzg back into your library.
When Ggorulluzg enters, search your library for a number of basic lands equal to the number of slugs, frogs, and horrors you control, reveal them and put them into your hand.
Whenever a land enters under your control, you may sacrifice it, if you do, create an x/x black and green slug horror creature token, where x is the number of lands in your graveyard.