Derek hears the tone in Neil's voice, and part of him thinks that he's right, that maybe should turn and go. But Derek has never been one to run away from a fight, and this thing is heading for them like it's going to track them even if they run. It's singularly focused, and when it gets closer it opens its gaping maw to reveal an unending circle of jagged, needle-like teeth. They're slick and dripping, and Derek feels his own fangs drop in response.

The thing hisses and Derek roars, shifting into beta form as his eyes glow red. Dimly, somewhere in the back of his mind, he thinks about how he didn't want Bitty to find out this way. But the thought vanishes as the thing lunges forward, and Derek throws himself at it before it can get closer.

It feels slimy and scaly all at once and Derek's claws drag through the thing's hide, trying to find arteries or tear at muscle. The monster's blood comes out thick and black, and Derek lets out another roar as sharp teeth sink into his side. He whips around and finds the beast's mouth, digging his claws in just underneath and raking them down, tearing away what passes for the thing's throat. It lets out a shriek and gurgles, falling limply to the ground. It twitches and then goes still, and Derek looks down at the wound on his side. Blood is seeping through the cotton, staining it red, but it isn't too bad. He has no idea how long it'll take him to heal, but he can already feel a vague itch under his skin, the beginnings of healing.

His face shifts back to that of a human, but he still feels too threatened to retract his fangs and claws. He turns back to Neil and Bitty, eyes wide and red, and he's fully prepared to see Bitty look at him like he's a monster.