How will enemy mobs be spawned?

Different mobs should spawn in different ways. Like alien mobs should spawn from UFO's that you can destroy, Reptiles should spawn from nests that you can destroy, zombies from dead human-like mobs,virorbs should spawn from theie respective element. Also, extinction could be cool. And breeding. If you kill all of species, no more of that species will be on the planet. If there are at least...like 10 spawners(depending on world size) on a planet, then mobs can create more spawners( ufos, nests) but after you destroy a set amount, or there a few left, no more spawners for that species can be made. So fewer mobs spawn, and eventually they go extinct.

 

They should all spawn all at once right at your character, like right in the center of your torso.

 

I would like to see a starting number of creatures, then they attack each other and breed according to species. That way you could have a true ecosystem of sorts. Then perhaps have "infected" zombie planets with zombies, and evil spawning offscreen.

Then have the player fight nasty predators on normal ones.

 

It could just spawn outside you FOV. This way there is no mobs spawning behind your back.... or the "Creeper Effect"

 

I think the Terraria spawn system was pretty decent. Although the thing with being able to wipe them all out is a little tricky. See, here you're all already suggesting breeding and the sorts, where it's, at least for me, pretty clear that we won't have breeding in this game unless otherwise announced.

 

Terraria spawning wasn't that great.
I think that it would be interesting if they spawned in the darkness, like in Minecraft. Also, I think the King Arthur's Gold developers have got the right idea. Terraria's spawning was "subtle". Balls to it, I think it's brilliant that if you are at the edge of the map you see Zombies splorg up
True, there's not going to be any 'edge of the map' on a planet, but still.

Not all of the mobs would make sense if dropped by a UFO, but that's a possibility. Also, there could be several spawners that spawn in the World gen.

And I do hope that it doesn't work like Terraria where the monsters just de-spawn when you're not looking, that is quite ridiculous *coughKAGdoesn'tdoitcough* What?

Right, this is a good point. Thing is that in Terraria they're blasted to pieces. Here they probably have a 'dead' stance. Also, dead bodies should stay put! Like old Tomb Raider games. And maybe after a few days they could be bones. Maybe then you could use bones to create stuff!
But yeah, if you kill them right away with a gun, you may need tranquilizer darts.

~ockpii