Blooper Baby

Blooper Babies, alternatively Bloober babies or Baby Bloopers, 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 Bros. 3
They first appear in Super Mario Bros. 3, where they are children of Bloobers with kids and swim in a straight line when released by Scattering Bloobers.

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 past games. As Blooper Nannies do not appear in New Super Luigi U, Blooper Babies are absent as well.

Super Mario Maker series
Blooper Babies reappear in Super Mario Maker, Super Mario Maker for Nintendo 3DS and Super Mario Maker 2 along with Blooper Nannies. Unlike previous games, the Blooper Nannies do not release them at Mario.

The Adventures of Super Mario Bros. 3
Bloober babies make a few rare appearances on The Adventures of Super Mario Bros. 3, where they appear alongside their parents. In "Oh, Brother!", a Bloober with kids is seen in Pipe Land, just like in the game. In "Recycled Koopa", a Koopa Zombie releases Bloober babies from a ketchup bottle after squeezing it.

Nintendo Adventure Books
In Leaping Lizards, Luigi can spot some 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
Bloober babies appear again alongside a Bloober with kids in Super Mario RPG: Legend of the Seven Stars. Touching one of them starts a battle with a normal Bloober.

Paper Mario
In Paper Mario, Blooper Babies are released by the Super Blooper. They attack in the same manner as Fuzzies.

Dance Dance Revolution: Mario Mix
In Dance Dance Revolution: Mario Mix, Blooper Babies, referred to as mini-Bloopers, appear during the Big Blooper Battle of World 2-4. They can be stepped on if timed with the beat, but if missed, ink will spill to the bottom on the screen, hindering visibility of arrows.

Mario Kart Tour
In Mario Kart Tour, Blooper Babies makes a cameo appearance on the Blooper Hanafuda glider. This glider uses the same Blooper artwork from Mario Hanafuda.

Other appearances
In the Super Mario Mash-up in Minecraft, the original game's Ink Sacs are replaced by a Blooper Baby item.

Trivia

 * In Super Paper Mario, Blooper Baby graphics exist unused. Both it and the normal Blooper are labeled as test enemies.