As any other rubber duck, it is a yellow duck-shaped toy with an orange beak and two black eyes. It often wears a Waluigi cap as well.
- The Wacky Wario Bros.: The Winning Ticket.
- SM64: ṩṩἔᾗмὄḋᾗᾄʀ 7 (TOAST edition)
- SM64: ṩṩἔᾗмὄḋᾗᾄʀ 8 (150k special)
- The Wacky Wario Bros.: Money Mayhem
- SM64: The Retardness of 2014
- The Wacky Wario Bros.: Golfing for Gold
- SM64 Bloopers: The Pirate Plumbers
- SM64: War of the Fat Italians 2015 (600k Special)
- SMG4: Waluigi's Time
- SMG4: The Mario Café
- SMG4: Wario Tries To Stop Himself From Dying
- Despite being an inanimate object, the Rubber Ducky seems to be capable of speech, as demonstrated in SM64: ṩṩἔᾗмὄḋᾗᾄʀ 8 (150k special).
- Kirby mistook it for fried chicken and ate it in The Wacky Wario Bros.: The Winning Ticket..
- Wario hates the rubber duck because Waluigi makes some quacking noise with it, which annoys Wario a lot.