A group of new born Zillas they behave a lot like the raptors from "Jurassic Park". Most were killed in "Godzilla(1998)" movie but one survived and is seen in both the movie and series where it because Zilla Jr..
Godzilla: The Series
Only one baby Zilla is ever seen and it eventually became Zilla Jr..
Since all Zillas were originally ment to be another version of Godzilla, it is very likely that Baby Zilla is a homage to Baby Godzilla/Little Godzilla/Godzilla Jr, in fact one of them lives to surpass his father just like Godzilla Jr..
The 1998 movie in which Zilla first appeared under the name Godzilla. Its sequel is "Godzilla: The Series".