Just had a weird interaction with a colleague

Colleague: We need to make Project X our number one priority. I have heard many people on Tracy's team talk about how great it is.
Me: I actually attended a workshop about it last weekend. Good idea, but not a top priority.
Colleague: I've heard people talking about it. It will save lots of money.
Me: Lots? How much is lots? I don't think it's that much.
Colleague: It's a lot.
Me: How much though?
Colleague: A lot. I've heard people talking.
Me: But how much?
Colleague: A lot. Trust me.
Me: How much is a lot though?
Colleague: I've heard people talking! Why don't you trust me?
Me: I would need an estimate. Let's call Tracy.
Colleague: I don't like your attitude. It will save a lot and I refuse to believe otherwise.
Me: *calls Tracy* Tracy how much would Project X save?
Tracy: Not a ton, maybe two grand? Not nearly as much as Project Y.
Colleague: I guess we just think different opinions. I still think we should pursue it. I don't believe Tracy.

Serenitree · F

I know exactly how you feel about that bizarre attitude.

They try to convince you that they are right, based on information they claim to have got from someone else. When confronted with that somebody who disagrees with them, do they back off? Nope. They say that person is not the most reliable source.

IF I was that person's boss/supervisor, I'd be doing a job eval on their job performance and maybe giving them a big demotion.