Tri-phonic Undulating Nanobot Automaton
From the Super Mario Wiki
The Tri-phonic Undulating Nanobot Automaton or TUNA for short, is a machine created by Dr. Crygor that appears in WarioWare: Touched!. It is capable of making objects younger. During Dr. Crygor's story, Dr. Crygor first tests the machine out by placing an apple core inside the machine. The machine then spits out a complete apple core. Dr. Crygor then goes inside the machine, where the player spins the wheel of the TUNA to make it work. Once done, Dr. Crygor emerges, revitalized, and being able to live for another 437 years.
The machine serves as the background during the microgame sequences where the player plays Dr. Crygor's microgames.