When Skye was shown the goop, it looked a little different than the last few times she'd seen it. There being a smaller amount wasn't surprising, considering she knew that Gavin way running a variety of tests on the stuff.
It was basically magic in physical form, but with hostile intentions. Any time Skye went near it, it reached to her. He didn't know if it was her magic, bloodline, or something entirely different; but every time Skye went near the ooze, it tried to latch onto her.
When she told Gavin that Richard had called her the Catalyst, he started to think about the different wavelengths that both magic, and light operated on. Taking out all the terminology: it was all energy. Existence itself functions on the fluctuations of energy, at least to Gavin.