How do you spawn mobs?

So I've been in/seen screenshots of servers where admins spawn hundreds of mobs (like slimes...zombies..even hornets! (got me full cobalt that day). How do they do it?

they have to have Tmod, Tshock, or something similar, and type /spawnnpc <number> "name of mob" "player"

the version of tshock we use is /spawnmob "<name>" <number>

The "are for mobs that are two or more words. <name> can also be substituted with their ID

Well, I personally think it's cheating to keep drops from spawned monsters. It's not a challenge to get a Robot Hat if you can spawn a million Piranhas.

Anyways, you need a mod like tMod to do this.

You could get Tshock or Tsdm (i think that's how you spell it)

Cobalt? Using an out-dated version I see....

TDSM - Terraria Dedicated Server Mod. ;P

I thought I misspelt it...thank you!