Behemoth radiation 1

Behemoth was glowing, his gray skin tending more towards white, a stark contrast to his obsidian horns and claws. The heroes were backing off a measure, and Behemoth was taking advantage of the situation to stampede forward, tearing past buildings and barricades.

“Grue!” I shouted. The noise in the distance was getting worse. If Behemoth was continuing the path I’d seen him traveling, he was wading through a series of buildings. Grue didn’t hear me. I raised my voice, waited until the noise died down, “Radiation! Use darkness!”
[...]
And just beyond this point, Behemoth, in the flesh.  He glowed white, marking the radioactive glow, and Grue’s darkness wreathed him, containing it.

- Crushed 24.2