Specific Supernatural/SG-1 crossover

[almne.livejournal.com]

Okay, I'm looking for a specific crossover where a shapeshifter somehow gets into the base of the Stargate SG-1 (I think). I also think Sam and Dean were on the tail of the creature, and have to break into the base as well. The Stargate people were treating the Shapeshifter as they would an alien, which wasn't working. I think they wound up catching the Winchesters at some point after they had broken into the base. I'm pretty sure it was gen, and set either 1st or 2nd season of Supernatural, definitely no later than 3rd.

It's not "The Same Coin" byyacoba, and I've gone through all of the SG-1/Atlantis tags here, and none of them jumped out at me as being this story.