At the beginning of your end step, if you control a creature with power 4 or greater, draw a card
Pair it with Cackling Counterpart, for instance, and you can get five copies of any creature you want
Well call our familiars to dispose of these corpses: Blade of the BloodchiefBlade of the Bloodchief, BloodghastBloodghast, Butcher of MalakirButcher of Malakir, Dusk Legion ZealotDusk Legion Zealot, Glass-Cast HeartGlass-Cast Heart, Heirloom BladeHeirloom Blade, Kindred BoonKindred Boon, Martyr of DuskMartyr of Dusk, Nighthawk ScavengerNighthawk Scavenger, Oathsworn VampireOathsworn Vampire, Radiant DestinyRadiant Destiny, Sorin, Lord of InnistradSorin, Lord of Innistrad, Temple of the False GodTemple of the False God, Windbrisk HeightsWindbrisk Heights
It's been errata'd from a 'carriage' (which implies the creature represents the whole unit) to 'Horse', so I guess the flavour of the mechanic is the horses just being lazy until they are 'fed' with a creature
The detail really makes the monsters jump off the page
The closest comparison I can think of is Phyrexian Arena, but Arena doesnt whiff just because you have no creatures