Emri, Uncanny Wanderer

All Horrors you control gain +2/+1 and Menace.
When Emri, Uncanny Wanderer enters the battlefield, gain control of all Horrors.
Whenever a Horror deals combat damage to a Player, that player may draw a card and put a +1/+1 counter on target creature. That creature is a Horror in addition to its Creature types.

"I have decided to slake my own curiosity rather than sate my hunger"