[2021] Zombie / Dog / Wolf dropping out of thin air (BUG?)

Honestly, It sounds like one of your friend group has admin access(Or cheat engine or something like it) and is using the spawn menu to screw with everyone.

However, setting that option aside for the moment, It's also a possibility that whoever is hosting doesn't have the computer performance required to host. The games spawning director does it's best to spawn things out of view of the player whenever possible, however if it is falling behind in it's spawning, it will start taking shortcuts by skipping spawning rules in order to catch up, by allowing spawns within view, by allowing spawns closer to the player, etc.

Originally posted by Teresa: I agree totally with @Shurenai.

It sounds exactly like someone is spawning in the mobs. Most likely one of your friends is laughing his butt off.

The game's spawning director struggling because it is falling behind is a good second guess,

However, a friend spawning things in for fun and excitement is like 98%, spawning director 1.9%, and weird bug 0.1%.

Chat with your friends lol.

Tbh it's more like 98% friend, 1.9% weird bug, and 0.1% spawning director.. As the spawning director, even when taking shortcuts, should never be spawning 25+ aggroed enemies at one time in any normal circumstances, even if the server is totally overloaded.