terraria how can i create a multiplayer world so that when people spawn in it they spawn in lava and immediately die?

Answer 1

Blow up a huge pit above the spawn, fill it with lava, make a bed for you to spawn on!

Answer 2

Not recommended as this is called Griefing.

Though make a new character and pinpoint the original spawn.

Place lava underneathe the character and add spike for an added effect so they cannot escape. However, adding Meteorites around that would get the Meteor heads to spawn so its even harder to survive. However, they can't always immediately die as they might use blocks to remove the lava or even a obsidian skin potion.