According to IGN’s Matt Casamassina, Halo on the DS once existed. He apparently got the chance to play the game before it got unfortunately canned. Microsoft and an unnamed publisher had been working on the Halo DS project but had to cancel it due to a couple of issues and differences.

Matt wrote about the leaked Halo DS game he had gotten the chance to play:

Amazingly, the ill-fated DS version of the title plays remarkably well. Think Metroid Prime Hunters but with a Halo facelift. I had the opportunity to run through the beginning beach area and noted while playing that it looked like Xbox Halo except on DS, it was running fast, and the control was responsive. The trademark Halo music even played out of the tiny speakers of Nintendo’s handheld.

It is very unfortunate that this game couldn’t have been continued on, the idea of Halo for the DS, as strange as it seems, would have undoubtedly been a massive hit. Check out his blog for more information.