Baa is the navy blue Tiddlytubby. He has a sphere shaped aerial and also has a darker skin tone like Dipsy and Duggle Dee.

He was one of the first Tiddlytubbies introduced in the episode Babies. Then from the episode Tallest Shortest until the end of Season 1, he was seen playing on a bouncy swing.

In Season 2, the Tiddlytubbies were given their own characteristics. Baa always likes to play boo and enjoys sliding and bouncing in his bouncy swing.