When you hear the hooves of bone striking the earth and see its black wings spread, it's already too late.
The Grim Stallion is Death's themed horse, released in version 2.8.2. It can be bought for 200 Sheriff Stars after becoming a Bronze VIP in the game. Alternatively, it can also be won in the Gold Lottery. It has a gauge overflow on Trot (slightly) and Gallop.
Being Death's horse, it has black wings similar to what a demon has, and a zombie like character.
Dark energy is emitting from it (as a tail and neck mane) like the weapons that Death uses.