Necroth devourer of souls

+3: place a +2 +2 counter on any creature if that creature is a skeleton, elemental or necromancer they gain +3 +3 instead
-2: you have an unlimited hand size and can now cast from your graveyard
-10: sacrifice all of your creatures except for your weakest one (even planeswalker) that creature gains the strength toughness and abilities of them.