As soon as the lights went off, Sol knew something was very wrong. The black ichor that had been humming at the edges of the classroom swept into the space around them and rushed to fill their ears and noses.
The thing pressed into his core, attempting to take him, possess him, but he didn't let it. He pushed back into treeform and hardened his lungs, he could feel his teammates repelling the entity with their own powers. Yet, even as they fought it off, more of the strange substance – neither shadow nor vapor – poured from the walls to fill the room like a swimming pool. It heaved and pushed against them like sentient water.
"Weak little treant," he heard the goo whisper in his ear. It wasn't one voice, but a thousand that echoed into his skull.
Felicity let loose in a fit of rage and sliced at it, only to find it acted like vapor at one second, and solid goo another. It pulled against their every movement, attempting to drown them in whatever abyss it was becoming.