Giant Three-headed Snake

The Three-Headed Snake is an anime-only animal in the 1999 series.

Appearance
Like its namesake, it has three heads and it has thick red and purple lines that go across its entire body.

Hunter Exam arc
A tour guide to the animal show held on Whale Island, introduces the Three-Headed Snake and details that each head has an individual name: "A-chan", "B-chan", and "C-chan". Later in retaliation for being locked up, Gon releases all of the caged animals at the animal show.