Cereal Killers

Creatures you control with Mascot are Horrors in addition to their other types.
Horrors you control have Mascot. The same is
true for Horror creature spells you control and
Horror creature cards you own that aren't on the battlefield. (When a creature with Mascot enters
the battlefield, search your library for a card with
Mascot, reveal it, put it into your hand, then shuffle
your library.)