Spot, Chaos Incarnate

Spot, Chaos Incarnate's toughness is equal to the
number of Spiders you control.
At the beginning of your upkeep, exile the top
four cards of each opponent's library. You may
cast spells from among cards in exile this turn.
{w}{u}{b}{r}{g}, Sacrifice a Spider: You may cast any number of spells from among cards in exile
without paying their mana costs this turn.