Spike thought for a moment, before raising his hand. "Death cap mushrooms are poisonous," he said softly. "I don't know exactly what the poison in them is called - amanit...something, maybe? - but it mainly affects the liver and kidneys." Or at least, that's what he'd been told when his father had found some suspicious looking fungi in the woods where Spike had his den.

And as for testing it on a rat... Spike's eyes narrowed. He wasn't a fan of rats, but then many people weren't fans of tarantulas - and Spike definitely wouldn't have allowed that. It was still innocent. And it wasn't for another useful reason either. He crossed his arms across his chest. She'd better not test the poison, even if she was just stringing them along.