Blooper Babies, also written as Bloober babies, are infant Bloopers. In most of their appearances they are often seen alongside Blooper Nannies, a species of female Bloopers who release multiple Blooper Babies when they glow, afterwards Blooper Babies will follow their mother and help her pursue Mario.
Super Mario series
Super Mario Bros. 3
They first appear in Super Mario Bros. 3, where they are released by glowing Blooper Nannies, and swim in a straight line after released.
New Super Mario Bros.
They appear in New Super Mario Bros. along with Blooper Nanny where they behave exactly the same as in Super Mario Bros. 3. They only appear in large numbers in a bonus room of World 3-3.
New Super Mario Bros. Wii
Blooper Babies and Blooper Nanny reappear in New Super Mario Bros. Wii where they behave in the same way as in New Super Mario Bros.. In this appearance they appear to lack pupils. They can only be found in World 4-4.
New Super Mario Bros. 2
Blooper Babies reappear World 3-5 of New Super Mario Bros. 2 along with Blooper Nannies. They behave the same way as in preceding titles.
New Super Mario Bros. U
Blooper Babies, as well as Blooper Nannies, appear in New Super Mario Bros. U, being featured prominently in the level Blooper's Secret Lair. They behave the same as in the past games. As Blooper Nannies don't appear in New Super Luigi U, Blooper Babies are absent as well.
Super Mario Maker/Super Mario Maker for Nintendo 3DS/Super Mario Maker 2
Blooper Babies reappear in Super Mario Maker, Super Mario Maker for Nintendo 3DS, and Super Mario Maker 2 along with Blooper Nannies. Unlike the previous games, the Blooper Nannies do not release them at Mario.
The Adventures of Super Mario Bros. 3
Blooper Babies make a few rare appearances on The Adventures of Super Mario Bros. 3, where they appear alongside Blooper Nannies. In Oh, Brother!, Blooper Babies are seen following a Blooper Nanny in Pipe Land, just like in the game. In Recycled Koopa, A Koopa Zombie releases Blooper Babies from a ketchup bottle, after squeezing it.
Nintendo Adventure Books
In Leaping Lizards, Luigi can spot some Blooper Babies (known here as "Bloober babies") if he falls into a body of water, and is pulled under by an Anchor he picked up.
Super Mario RPG: Legend of the Seven Stars
They appear again alongside Blooper Nanny in Super Mario RPG: Legend of the Seven Stars. Touching one of them starts a battle with a normal Blooper.