From Sonic Retro
Unidus (ウニダス) is a Eggman robot encountered as an enemy in Sonic Adventure and Sonic Adventure 2. It is an evolution of the old Orbinaut model badnik from the 2D Genesis games, and is often referred to by the same name depending on translation. Uni is the Japanese word for "sea urchin", and these robots live up to the name with their floaty, spiky attack method.
In Sonic Adventure, this badnik was known as "Spiky Spinner".
The fourth variation of the Orbinaut model, it's most close in design with the Orbinaut appearing in Sonic 3. It attacks in two ways, either throwing their spike balls at its enemy or by sending them in arcs for a wide radius attack.
|Tails||Sky Deck, Speed Highway|
|Knuckles||Speed Highway, Sky Deck|
Sonic Adventure 2
Unidus (ウニダス) reappears in Sonic Adventure 2. This model is basically the same as the one in Sonic Adventure, but it won't throw its spikes, bustling around randomly instead. It awards 100 points when destroyed.
|Sonic Adventure 2|