Ghoulsteed [Ultimate Masters] Dwarf Rogue Set: Sun & Moon: Unified

Set: Sun & Moon: Unified Minds Type: Psychic Rarity: Holo Rare Retreat cost: Colorless

Set: Mystery Booster Type: Creature — Zombie Fish Rarity: Common Cost: {6}{B} Delve (Each card you exile from your graveyard while casting this spell pays for {1}

The odds are good

(Leads to: Sandfall Cell) Sandfall Cell — Each player loses 2 life unless they sacrifice a creature

Without it

Ghoulsteed [Ultimate Masters] Dwarf Rogue Set: Sun & Moon: UnifiedSet: Ultimate Masters Type: Creature Zombie Horse Rarity: Uncommon Cost: {4}{B} {2}{B}, Discard two cards: Return Ghoulsteed from your graveyard to the battlefield tapped. It once served a cathar roadwatcher, patrolling the crossways between villages. Its hooves still carry it along the same path.