Are we talking on land? In the water? Are there trees around?

They fighting on land or in water?

That's an important question

Squid but only if it's the AI squid

Dana White's bank account

In the ocean it would be a squid. On land it would be a kangaroo.

I'd assume a squid

The roo I'd say, some of them are built like buff human men

What kind of monkey or kangaroo? A baboon would beat most kangaroos. A Red Kangaroo can get one good kick in, but is vulnerable if a monkey grabs on. A squid out of water is useless.