Qbaby

Qbabies are small box children that appear in BYE-BYE BOXBOY!.

Physical Appearance
Qbabies look similar to Qbby, however they are slightly smaller with little cheeks. In the third game, Qbabies also have the back corner of their heads colored, ranging from either red, orange, blue or purple.

BYE-BYE BOXBOY!
The Qbabies debut in BYE-BYE BOXBOY! as NPCs that need to be rescued and brought to the end of the level. They follow Qbby as he progresses through each stage. The Qbabies can jump over small gaps and steps, as well as ride blocks spawned by Qbby.

BOXBOY! + BOXGIRL!
There are small Qbaby look-alikes, though it is unknown if they are Qbabies grown up. They do not have the colored back corners of their heads, however they have colored cheeks unlike Qbabies.

Trivia

 * It is unknown if the Qbabies are all related or not.
 * It is also unknown who their parents are, as well as their genders (Unless you count the two Qbaby look-alikes from BOXBOY! + BOXGIRL! as one of them has a bow on her head, depending on the various scenario).