Crawltipede

The Crawltipede is a Hardmode, post-Lunatic Cultist, worm-like enemy which spawns in Solar Pillar areas during the Lunar Events. Uniquely, it has no health bar, and instead can only be destroyed by damaging its tail, which can be difficult to hit. It flies directly at airborne players and deals high damage, while ignoring players on the ground.

Crawltipedes' primary role seems to be forcing the player to stay near the ground, opening them up to melee attacks from the other invasion enemies.

Tips

 * An unusual and perhaps somewhat dangerous method of dealing with the Crawltipede is waiting for it to curl up, then using the Cosmic Car Key to hover on the inside of its curl. The Crawltipede cannot turn sharply enough to reach you, instead forming a circle around you. You can then attack it from within its own “trap.” The only issue is that there isn’t much room to move without touching the Crawltipede’s body, so you’ll be susceptible to Corites until the Crawltipede has been killed.
 * This enemy does not target players on platforms no matter how high they are.
 * Using an item with limitless flying, like the Cosmic Car Key, very slightly above the ground will still keep the player safe.
 * The Crawltipede will approach flying players quickly and can deal massive damage. It moves swiftly and is able to make quick sharp turns, its mobility is far beyond any other worm-like creature. It is very hard to dodge even with high tier wings. Because of this, it is recommended to avoid this enemy as much as possible.
 * A player suspended by grappling hooks will not be targeted by the Crawltipede, unless the hook was the Static Hook or the Anti-Gravity Hook
 * Short jumps into the air are usually possible, but it is important to land again quickly.
 * Homing and fast hitting weapons such as the Razorblade Typhoon, Possessed Hatchet, or Chlorophyte Bullets will make fighting a Crawltipede much easier. Likewise, minions make short work of this enemy as they will target the tail without the need for the player to aim.
 * Vampire Knives are very effective against Crawltipedes, due their increased damage against them. This in turn rewards increased life regeneration, and thus players can very swiftly restore up to 40 HP (two hearts of health) with just one or two successful attacks.
 * If you have defeated the Solar Pillar before, the Solar Eruption is somewhat effective against the Crawltipede. Its swinging motion and long length can easily hit Crawltipedes' tails.
 * If using a powerful magic weapon and wearing Spectre armor with the Spectre Hood, hitting the tail can heal for 600+ HP, the highest self-heal per hit in the game.

Trivia

 * It is the only destructible enemy without a health bar.
 * The Crawltipede may be a reference to Moldorm from the fantasy action-adventure video game franchise  – more specifically, Link's Awakening, A Link to the Past, or A Link Between Worlds – where Moldorm appears as a giant black or yellow centipede that can only be damaged by striking its tail. It has a habit of attempting to knock Link into the pit surrounding the arena, similar to the Crawltipedes' habit of flying directly into an airborne player.
 * Should it happen to enter the area of another Celestial Pillar, its color changes accordingly.

History
Rampipède