More of Project T.A.H.I.T.I.'s past was revealed on Agents of S.H.I.E.L.D. Tuesday night, and I didn't like what I saw one bit. The Agents involved as test subjects were routinely wiped of their memories, but not their compulsions, after the GH-325 started showing symptoms and the patients started deteriorating. I'm still not entirely sure how that worked? I suppose it just slowed down the process. Also, that blue alien that GH-325 is made from showed up again. What is that thing? Why does it only have a torso left? Coulson and the scientist in charge of the Project referred to him as "the host."
The most popular theory is that the blue alien is Kree. In the Marvel Cinematic Universe, we first saw the Kree show up officially in this summer's Guardians of the Galaxy. However, there were also pink and green aliens in that movie. Not to mention whatever Groot is. The Kree aren't the only blue-skinned creatures in the Marvel World either. Mortal enemies of the Kree, the Skrulls are also kind of a blue-ish hue. They may be a bit more green, but it's not too far off.
For a while, I considered that the alien wasn't blue after all, just tinted by either the lighting or the fluids in the tube where he was being held. Then, the alien made a second appearance in this season's premiere when Peggy Carter busted open a Hydra cell and took possession of their stolen evil goods. We only saw a glimpse of him, but it appeared to be the same alien fellow. He definitely wasn't being kept as well as Coulson's team did in the future. Then again, he probably had more of his limbs in tact. As Fitz said, "Corpse Diem: Seize the Dead."
That also means that at one point, this alien was in the possession of Hydra. Not only does that explain why Whitehall and his crew are after the carvings, but it is not a good sign for the Agents of S.H.I.E.L.D.