Mr. Miggins is Candace Flynn's stuffed teddy bear. Based on his appearance, he has been with her a very long time, he is very worn down and old: Mr. Miggins has been patched at least twice, and has a loose eye and stuffing showing from his seams. Candace talks to Mr. Miggins as if she were talking to herself.
Mr. Miggins' current role is to be a "security blanket" for Candace and resided temporarily in the family's panic room. When she believes that her brothers have become robots, she runs to the panic room and clutches Mr. Miggins while calling her mom. When her mom doesn't come immediately home, Candace talks to Mr. Miggins about the robots and devises a plan for capturing one as evidence to show her mom.
At the end of the day when a robot version of herself is created, Candace runs back to the panic room. The Candroid has reached the panic room first and is holding Mr. Miggins. Candace quickly snatches her beloved bear from the robot. ("I, Brobot")
Later that summer, Candace brought Mr. Miggins back to her room. She was in the middle of trying to figure out what to wear to Stacy's costume party when she decided to ask "Jeremy" (Mr. Miggins with a picture of Jeremy taped to his face) what he thought. His stunt as a substitute Jeremy was short-lived when the real Jeremy called. ("Boyfriend From 27,000 B.C.").
Candace moved him out of harm's way when Suzy came over by temporarily placing him out of sight in a trash can. Other things stored in the trash can include "anything Suzy could use against" Candace ("Suddenly Suzy").
Candace later removed the picture of Jeremy off the bear when she decided to act more like an adult and was surprised to find Mr. Miggins after the picture was removed. Stacy also used Mr. Miggins as part of the shrine she made for the "Mysterious Force."(Phineas and Ferb The Movie: Across the 2nd Dimension)
Mr. Miggins' final appearance is amongst the rubble when Doof accidentally destroys the Flynn-Fletcher house in The O.W.C.A. Files.
- Heinz Doofenshmirtz also has a bear like Miggins ("A Hard Day's Knight").
- Stacy also owns a teddy bear with a blue bow very similar to Miggins ("Phineas and Ferb Summer Belongs to You!").
- Major Monogram also has a bear similar to Miggins, but it wears a fedora, referencing the O.W.C.A. agents that Monogram leads ("Excaliferb").