Magma Worm

Behavior:
The Magma Worm has a single attack in which the worm emerges from the ground, turns around, and submerges. The worm leaves a small patch of flame whenever it emerges or submerges, this indicates where it will emerge from. When fighting the worm, it is difficult to fight with other enemies around, as you may be forced to dodge into them. When on low health, the worm will strike faster and move faster, but will become less accurate. The worm consists of 20 total hit-boxes, however only the head deals damage.

On death, the worm may drop the Burning Witness item. The hitboxes also stay present until the worm despawns, meaning it is possible to continue hitting it after it dies.

Elite Version
Overloading Magma Worm This is the only elite version of the Magma Worm. The main difference is that the elite Magma Worm's skin is charged with electrical energy (much like the Tesla Coil on each segment of the worm), making its damage range about twice its normal body width. It is also observed that the Overloading Magma Worm's aim is much more accurate than its normal version. These two features together make it very hard to avoid damage each time it dives without an escape skill, double jumps, or very high move speed. The Overloading Magma Worm, like all other elites, has a significant HP increase. Killing the Overloading Magma Worm with the Loader will unlock the Gigantic Amethyst, and is a character specific achievement.

Each segment of the Elite Magma Worm has the ability to deal damage through its Tesla Coil-like effect.

Magma Worm

Tactics

 * This boss can be very easy to kill with area of effect abilities or abilities that hit more than one target, such as the Mercenary's, the Huntress' and , and the CHEF with  and then  because the worm has multiple segments that can be damaged.
 * Climbing onto a rope or vine can prevent all damage this worm deals, as it only deals damage through contact when it goes up or down.  However, the Overloading variant's shock effect will still trigger on the target.
 * Sometimes will rapidly change aggro even if the current target is alone and dealing it a lot of damage.  This means no players should be complacent if it is not targeting them.
 * Its arrow telegraph will sometimes lag or not appear at all, causing massive damage to unsuspecting players especially if it just spawned.  This is especially common with the Overloading Magma Worm with its increased damage radius.  Recommend all players stay on the move no matter what or when they hear a worm's roar.
 * With the latest update to targeting, its turn radius allows it to nearly hit any slower-moving character.  However, the Worm always turns its head "down" toward the lower part of its head.  If a player can get behind its body (out of under the slope it creates on rising), its "backwards" turn radius is severely limited by this movement.  Sometimes it can be worth dashing through the body instead of getting hit by a full-on charge.
 * Has a habit of spawning almost immediately on Monsoon difficulty.  This can lead to devastatingly short Glass runs.
 * When in multiplayer, its item drop on death will often not appear at the point of death, but instead near another player's character.  The host seems to be the one it most often ends up near.
 * Rockets and other seeking items are great but will lose targeting on the worm after it goes underground.  These need to be fired very close to it or immediately as it is rising, since its descent is much faster than most seeking projectiles. Similarly, any status effects on it will be removed.
 * To deal with the Overloading Magma Worm, use ladders to your advantage and go under it in the opposite direction it jumped out at you. Ranged attacks are the best way to deal with it as the Tesla Coil effect can end up dealing massive damage at close range. Most characters have at least one either large radius attack or an actual ranged attack. Chef is most likely one of the best counter-picks to this boss as his Second Helping basic attack can hit him multiple times in a single use.