From Earth-99476, also known as Dino-world, one of the many realities from the Multiverse of Alternate Earths, as chronicled in Excalibur.
In the ten or so issues approaching Excalibur #50, the Multiverse's many realities approached its cross-dimensional convergence, an event that occurs once every few millenia. Excalibur's lighthouse was the focal point of this event, resulting in various apparitions taking place in the other dimensions. One apparition was a battle between Punisaur and Dino-steel.
Dino-world's other heroes included such intrepid characters as Saur Fantastic, Invisiguanadon, Dinotorch, Nightstrutter, Shadowcompsognathus (who, in all likelihood, is also a ninja), Arachnosaur, and Brittanicus Rex. Excalibur visits Earth-99476 in issue #51.
We're watching Dino-steel's mammalian counterpart tonight.