Sounds like something out of one's imagination, especially coming from a child, but Lup's also grown up in a world of spirits and spells and monsters. An art gallery with living paintings that are probably shitty to children? Yeah, that could be legit.

Plus she literally saw the kid's magic rose, so. That all checks out.

"Well, it's good that you're here instead of there, then. If anything starts to chase you, just find me and let me know, okay? I'll set 'em on fire, just like that." She snaps her fingers with a smile.