This is the first track in the AU known as Bygone Era, a world at the core of the Earth.
The original composition was made by Goldjim(https://soundcloud.com/jimmy-nason), and was then remixed and finalized by Suspicious Spagetti(https://soundcloud.com/user-759879626)

Steggy

Oh shit does that Allosaurus have a bat
Original Composition by Goldjim, remix by https://soundcloud.com/user-759879626

Psych, Other Crusher

So this is Steggy's brother...
This isn't what you expected
Original Composition by Goldjim, remix by https://soundcloud.com/user-759879626
Phase 2 (https://soundcloud.com/bygoneerateam/allo-means-other)

Bygone Era Team