Gunk Slug - Symbol (CMB1) from Mystery Booster Playtest Cards 2019, available at 401 Games Canada.

• Rarity: Rare
• Finish: Normal
• Artist: Casey Gustafson
• Card Text:
  When CARDNAME enters the battlefield, create three Gunk token cards and shuffle them into target opponent’s library. (Gunk is a colorless sorcery card with no mana cost that has cycling (4).)