Vulcan Valley/Jim

Jim is a Hardmode boss that can be fought after Plantera has been defeated. It is essentially a boss version of.

Spawn
Jim does not spawn on its own, and requires the player to summon it with the in The Underworld at any time.

Behavior
Jim behaves similarly to most worm enemies, digging through blocks and attempting to ram the player. When initially spawned, it appears straight above the player and quickly digs down.

Attacks

 * When the player is close, Jim's head breathes close-range fire very rapidly.
 * Every 1.5 seconds, it spawns either 3 s or 1 until a limit is reached.

In Expert Mode

 * Jim breathes less fire, but occasionally shoots dangerous fireballs.
 * Instead of spawning 3 Jimmys or 1 Jimothy, it spawns 2 Jimmys and 1 Jimothy, or 1 Jimmy and 1 Jimothy.

Tips

 * A large arena that spans the underworld is recommended for this battle.
 * Try to target Jim's tail, as it has the lowest defense out of all of the body parts.

Trivia

 * Jim's theme is Solar Storm.
 * Jimothy was actually made before Jim, after which it was decided to make a larger version of Jimothy with more attacks, as the mod's first boss.