Medusa
Magic
Vendor
She hates head pats, hence the spiky armor.
How to Obtain
Vendor
Buy it from Thraxadar in Masters' Perch, then use the item to learn the pet. Requires Slayer's Duellum - Revered.
Where it comes from
The sources Medusa names in its in-game collection entry, each with its own page.
Also from Slayer's Duellum (3)
3D Model
First-party render from the game files. Model © Blizzard Entertainment.