The competitors aren't alone, the bad guys arrived as well to screw up everything and capture the competitors! (*Note that the bosses only appear in Adventure Mode or Boss Run mode)

  • Viral Wrecking Crane (Appears in the Local Neigbourhood)
  • Buga the Knut(from Conker's BFD; Appears in the Caveman Village)
  • George Volcano (Appears in the Cruise Ship area, but on an island since he threw a bottle of Volvic water at the ship)
  • Killer Jack-In-The-Box (Appears in the Playhouse area)
  • Bio-Weed (Appears in the Empty Field)
  • Papu Pau (Appears Out of nowhere)
  • Wurley (Appears in Space)
  • Planktondroid (Appears in Bikini Bottom)
  • Giant Mecha Bowser (Appears in Bowser's Basement)
  • Marx (Appears in the Galactic Asteroid Belt, firing lasers and other hazards at you)
  • World of Chaos (Appears in Subcon as the final boss)
  • The Harvester 6000 (Appears in Cybertron exclusively in Boss Run)
  • Evil Jimmy Wales (Appears in Wawikipedia exclusively in Boss Run)
  • Chaos Brain (Appears in Wawikia exclusively in Boss Run)
  • Bob Saget (Appears in the Unknown Area)
  • Wabokkun (He kidnapped Bokkun's love interest Cream the Rabbit, Oops I wasn't supposed to say that last part!)