Hell Mongrel (MH2) from Modern Horizons 2, available at 401 Games Canada.

• Rarity: Common
• Finish: Normal
• Artist: Robbie Trevino
• Card Text:
  Discard a card: Hell Mongrel gets +1/+1 until end of turn.
  Madness 2B (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)