Is Egg Heist a PvPvE mode?

The PvE half is the Lost Isles and the monsters in them: you fight through, gather eggs and resources, and the exclusive Aniimo eggs are the reason anyone goes in at all. The PvP half is everyone else doing exactly the same run. It is an extraction mode, so collecting is only half the job. You have to get out with the haul, and rival squads can kill you and take your items on the way.

That changes how you play the PvE side. Every fight you pick with a monster is time another team can use to find you, and anything you are carrying is worth more to them than whatever they might dig up themselves.

The mode goes by several names. Operation: Egg Heist, PvP Egg Heist, Diamond Egg Heist, Diamond Egg Stealing and diamond egg theft all point at the same thing. It arrived in the third beta, which is why the shape of it is still moving.

Chaos mode

Operation Egg Heist carries a hardcore variant called Chaos mode, the same heist run at higher difficulty. It sits as its own entry rather than something you turn up mid-run.

Why the format keeps changing

The structure is not settled. It has run as a competitive race between teams to collect eggs, as a PvP-only variant played in teams of three, as a real-time PvEvP run in the Lost Isles where three-player teams battle monsters and other players to gather and extract, as an objective-holding match between two teams, as a team-versus-team match with up to six three-player teams contesting a single objective, and as a cooperative version with no PvP combat in it at all.

The constant across all of that is the three-player squad and eggs as the prize. Lobby size and whether other players can reach you are things to check in whatever build you are playing rather than assume.

Not settled: A PvE-only cooperative version with no PvP combat has also appeared, so the PvPvE label describes the mode as a whole and does not guarantee that every variant you queue into puts you against other players.