Queen Slime

Queen Slime is an early-Hardmode Hallow-themed boss and is the Hardmode counterpart to King Slime. Her appearance is that of a massive, transparent pink slime wearing a tiara and engulfing a colorful crystal. Fighting Queen Slime is completely optional and not required for game progression, but her defeat may reward the player with useful items.

Spawning
Queen Slime can be spawned by using a Gelatin Crystal in the Hallow (if used outside of the Hallow, nothing will happen and the item will not be consumed). Once used successfully, the item is consumed, and the boss is summoned.

The Gelatin Crystal can be found in the Underground Hallow alongside Crystal Shards, and it spawns in the same way as Crystal Shards.

Behavior
Queen Slime jumps around in a manner similar to King Slime, though much faster. She summons minions as she is damaged that attack the player:
 * , which fire several crystals upward
 * , which fly toward the player
 * , which fire bouncing shots toward the player

After a few jumps, she remains stationary for a few seconds, then attacks in one of two ways, chosen at random:
 * Jumps quickly toward the player, attempting to stomp them, which deals high damage.
 * Fires 6 that bounce twice before breaking. She will sometimes perform this attack multiple times in a row.

When at 50% health, Queen Slime grows wings and begins to fly like a Slimer. Her AI also changes:
 * She rapidly fires Regal Gel in 10 directions.
 * She attempts to fly above and drop down onto the player, if the player is in close enough proximity.

Tips

 * Palladium armor can be useful due to Rapid Healing buff it provides.
 * Queen Slime herself has a relatively simple attack pattern. Half the threat comes from the minions she spawns, which can fill the screen with projectiles and quickly overwhelm the player. Killing or avoiding these should be top priority.
 * Stay in the air using wings or mounts during her first phase, as many of her attacks cannot reach the player there. During her second phase, the player should stay closer to the ground while occasionally luring her back up, as they can avoid many of her projectiles and minions due to their slow and predictable movement patterns.
 * In Master Mode, The Black Spot mount allows the player to hover above all attacks in the first phase. It also goes faster than Queen Slime in her second phase. Be careful as getting too far away can despawn the boss.
 * Fight Queen Slime in daylight, since at night her attacks may be hard to see.
 * Queen Slime can be killed easily before any other Hardmode bosses, and even before destroying Demon or Crimson Altars. The Crystal Assassin armor she drops will help the player survive in early Hardmode.
 * As with most bosses, she is immune to lava, however her minions are not. An arena made of lava paired with Lava Waders or Terraspark Boots can make the fight significantly easier.
 * Use several disconnected platforms, which can allow her minions to fall down and away from the fight.
 * Any wings paired with flight-boosting accessories and the Shield of Cthulhu (for its dash ability) makes dodging most of her attacks easy (but does not take care of her minions).
 * The Daedalus Stormbow paired with Holy Arrows and summoned minions can take care of her minions.
 * When fighting her in higher difficulties, never remain directly above multiple Crystal Slimes. Their spikes can kill the player in seconds.

Trivia

 * Queen Slime's AI was created entirely by developer Grox The Great, while the visual effect was created by Yoraiz0r.
 * Queen Slime is one of 6 bosses with exclusive music, the others being the Empress of Light, Plantera, Duke Fishron, Moon Lord, and Queen Bee.
 * The feather covered in slime on her trophy resembles the sword covered in slime from King Slime's trophy.
 * Queen Slime was one of the two bosses added in the 1.4 update, along with the Empress of Light. Both are Hallow-themed.
 * Queen Slime is one of the three bosses whose map icon does not change upon entering their second form, the others being the Brain of Cthulhu and the Santa-NK1.
 * Most of Queen Slime's drops are upgraded versions of King Slime's drops. Both the Ninja armor and Crystal Assassin armor provide general bonuses to damage. Each boss also drops a mount-summoning item (Slimy Saddle and Gelatinous Pillion) and a hook (Slime Hook and Hook of Dissonance).
 * Unlike most boss loot drops, the Hook of Dissonance is not affected by Luck, and so will always drop with a chance. This might be because of the Hook of Dissonance being Queen Slime's counterpart to King Slime's Slime Hook: The latter is also unaffected by Luck, because if the Slime Hook does not drop, the Slime Gun will drop.