Appearances on the show
Baby Duff is shown to have super human strength, a trait he shares with their maid, Queegee, who appears in Take Elmyra Please. In this episode, one of Mac's chemical mixtures explodes, causing Baby Duff to awake from his crib and spotting his teddy bear under a coffee table. He gets out by bending the bars on the crib and knocks over the coffee table to get it. He continures to wreck havoc as his mother calls for the rest of the family to help. After a few mishaps among themselves, Duncan manages to get Baby from under a rug he was crawling under with a little help from his mother (who passes him the pacifier to get Baby to go back to sleep). Mac has a huge announcement to make, but it will have to wait until Queegee takes Baby back to his room. Later, Elmyra's kidnappers slip a ransom note under the Duff's front door, but Baby promptly grabs the note and eats it. After Elmyra is freed, he appears with his family on a newscast about it.
In Grandma's Dead, Baby watches Furrball get chased up to the curtains by Byron Basset from the breakfast table. In this episode, he does not display any of his super strengths and acts like a typical baby (playing with his cereal by tossing it about and being carried around in his mother's arms).
Appearances outside of Tiny Toon Adventures
Baby makes a cameo appearance in Animaniacs in the Pinky and the Brain cartoon, Meet John Brain, where he can be seen alongside his father, watching television during The Brain's broadcast. Ironically, he did not appear in any episode of Pinky, Elmyra, and the Brain.