In Jelly Egg
In Jelly Egg is a common throwable item.
Can be used to spawn a jelly called in jelly, or a “cave” jelly in alkey.
These “eggs” are really just highly incubated versions of creatures, used by altas during research, often for simulation purposes, which is why they tend to be friendly to their owner.
Ingame
Species descriptions:
- Alta: A regular tiny, harmless, slimey jelly. How are you doing, jelly?
Sources
Can be obtained via 
Spawnable Item Pack or 
Technical Information
- In-game ID:
ct_in_jelly_egg - Power:
1.5 - Rarity:
Common - Tags:
common,monster_egg,spawner,throwable - File:
/items/active/alta/spawners/critters/ct_in_jelly_egg.activeitem