Main article: Bosses
Betsy is a Hardmode, post-Golem boss that spawns in the 7th (the last) wave of the Old One’s Army event. Like all enemies in the Old One’s Army, it will despawn upon completion or failure of the event. When Betsy is defeated, the progress of wave 7 will reach 100% and the event will be completed.
- The way Betsy attacks is a similar manner to Duke Fishron since she flies and spews projectiles. Unlike Duke Fishron, however, she does not have additional phases as a boss.
- Unlike most enemies present in the Old One’s Army, Betsy will charge directly at the player and won’t attack the Eternia Crystal itself unless the player moves far enough from Betsy.
- Betsy alternates between four attacks:
- She flies in a large loop, before dashing at the player multiple times.
- She goes to the edge of the screen, and flies horizontally, 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.