Rek'Sai, the Void Burrower

At the beginning of your end step, Rek'Sai, the
Void Burrower phases out.
Other Horror creatures you control get +1/+1
When Rek'Sai, the Void Burrower
phases out, create a 1/1 Horror
creature token.
When Rek'Sai, the Void Burrower phases in,
it gains haste.