If moulds were just dangerous substances, that would only be half of the problem.
Moulds are aggressive living organisms, in my opinion one of the strongest [if not THE strongest] microscopic entities I know about to this date.
To "mess around" with them is 'to ask for it', period.
When Rabbitears says: "You maybe messing around with something that you shouldn't.", perhaps she's giving the poster the warning of a lifetime.