Dr. Andonuts is Jeff Andonuts' father. He is a reformed scientist in Porky's army in Mother 3. He is Jeff's father. Although he never reappeared in Mother 3, the Dr. Andonuts there could be an old Jeff.
 Mother 2
In EarthBound, he is Jeff's father, living in his lab in Winters with his caveman assistant. He only has two uses in the game: he gives Jeff the Sky Runner, and gives Ness and co. the Phase Distorter.
 Mother 3
Dr. Andonuts first appears when the Ultimate Chimera is upon Lucas and Boney. He tells Lucas the Chimera's weakness, and also jokingly tells him to use Boney as bait (although it doesn't seem like a joke at first). He later appears to help Lucas pull the second needle, offering him three Chimeras that can be used.
Dr. Andonuts later appears when Porky enters the Absolutely Safe Capsule. He states that Porky is absolutely safe; nothing can get in once it closes, and nothing can get out. He feels sad for resigning Porky to a fate of living in a capsule for eternity. He stays at the capsule, and if talked to enough, rolls it to show how safe it is.