Space Gun

This weapon uses your maximum mana and shoots at a fast speed. Each bullet inflicts about 15 damage to a monster. This gun has no selling value to the merchant.

Unlike most Guns, the Space Gun doesn't use Musket Balls or Meteor Shot, instead using the Player's Mana to power it. This gives it a potentially unlimited supply of ammo. It's recommended to use Meteor Armor, Cobalt Armor, or a Band of Starpower with the Space Gun, as they boost your mana regeneration rate, allowing you to fire more often.

To prevent the gun being able to fire nonstop, you don't regenerate mana while you shoot it, including when you hold down the button for "Auto-Fire", meaning that no matter how fast your mana regenerates, if you fire non-stop, you will eventually run out of mana. But with proper gear, a decent sized mana pool, and a staggered firing rate, it's possible to fire almost non-stop.

It should also be noted that the beam goes through enemies, making the gun incredibly useful in areas where you can hit multiple monsters at once and particularly good against the Eater of Worlds. The shots also have very little knockback which, combined with the penetration of the beam, means that you can easily land multiple hits on clustered enemies without knocking them out of your line of fire.