The Abyssal Whistle is a Pre-HardmodePet summoning item that has a chance to be dropped by any enemy in The Underworld. It spawns an Abyssal Bunny to follow you around. The Abyssal Bunny is immune to damage from enemies and despawns upon player death.
If the Show Donator Item Colorconfiguration option is disabled, the Abyssal Whistle will have a rarity of instead of the standard .
The Abyssal Whistle and Abyssal Bunny are references to the series Made in Abyss. The Whistle is similar in appearance to the white whistles worn by top-ranking Delvers of the same name, while the Abyssal Bunny resembles a meinastilim.