The Ovomorph, known colloquially as the Egg, is an incubation chamber that contains a Facehugger. The Ovomorph is generally considered to be the first stage in the life cycle of the Xenomorph species.
The planet 4 variant of Ovomorphs functions similar to the ovomorphs of the XX121 strain, in that they are dormant until a suitable host approaches, however, the proximity needed to trigger them seems to be shorter as an egg did not open until Oram touched one. However, like the ovomorphs in the derelict's cargo, this could be the result of being dormant so long. Later when Cole is looking for Oram, another egg is seen already open despite there being no suitable hosts present until Cole entered.
The planet 4 variant also has a different interior, as whereas the typical eggs have a solid "york" with the Facehugger around it, the planet 4 version has a translucent sac with parasite inside it.
The chamber where the eggs are housed have a strong pungent smell coming from it, likely coming from the eggs themselves.
- In the novelization of Alien: Covenant, David shows Oram a fossilized Ovomorph and the dead Facehugger within, pointing out that they are an Engineer creation, engineered long before he arrived on the planet. David goes on to express a desire to play God, stating that he wishes to create a similarly "perfect" lifeform himself, apparently inspired by Engineers' past experiments that created first Xenomorphs. This is in strong contradiction to the film, which instead implies David is the originator of the Xenomorph species and creating them without any references from Engineers' past experiments.