Offers, what are they thinking?

About a week ago I received a call form a agent eager to show one of my listings, she called me back to let em know they would be making a offer and all sounded well.

I did receive the offer and it was for $85,000 on a $190,000 home. I spoke to the agent and jokingly asked if she forgot a one?

What is the logic in doing something like that. looking to steal something, unrealistic buyers or agents that are so un versed in the business that they don't know any better  or even worse don't care?

 The offer was of course presented to the seller who is still laughing.