Betsy

Betsy is a Hardmode, post-Golem boss that spawns in the last wave of the Old One's Army event, wave 7. She attacks by flying, charging, and spewing projectiles from above. Like all enemies in the Old One's Army, she will despawn upon completion or failure of the event. As soon as Betsy is defeated, the progress of wave 7 will reach 100% and the event will be completed.

Behavior

 * Betsy alternates between four attacks:
 * She flies in a large loop, before dashing at the player multiple times.
 * She moves to the edge of the screen, and flies horizontally across the screen, breathing a constant stream of fire downwards.
 * She launches many smaller fireballs that are affected by gravity.
 * She stands in place and roars. Two Etherian Wyverns will then appear beside her.

Tips

 * The On Fire! debuff is a major source of damage. Note that it negates life regen from Nebula armor's set bonus – hence, if you are unable to avoid Betsy's flame breath attack, it might make the armor ineffective.
 * The Obsidian Skin Potion can prevent the On Fire! debuff, however the initial hit from the attacks will still damage the player.
 * Use Bubble blocks to make a floating pool of water to cancel the On Fire! debuff. Honey will also cancel the debuff and also give extra life regeneration, but slows down movement while submerged in it.

Trivia

 * Betsy is the only event boss to drop a Treasure Bag in Expert mode.
 * The boss is based on the Betsy boss from Dungeon Defenders 2, as the 1.3.4 update brought a crossover event between the two games.
 * Betsy's attack behavior of flying and launching projectiles is fairly similar to Duke Fishron's. Unlike Duke Fishron, however, she does not have additional phases as a boss.
 * Betsy is one of the only enemies of the Old One's Army to focus the player instead of the Eternia Crystal.
 * She is one of the two Wyvern-like enemies that does not possess the Worm AI, the other being the Etherian Wyvern.

History
Betsy 双足翼龙