AITA for refusing to fund my boyfriends ‘genius’ idea?

I (F24) have been dating my boyfriend (M29) for 3 years, and while he’s always been a bit wacky I usually find it kind of endearing. This time however, he’s really outdone himself. A few weeks ago, he told me he had a “groundbreaking” idea that would “change humanity forever.” Entertaining him, I asked what it was. His answer? He wants to invent a new color.

Before we go any further it’s important to note we are both college graduates. I graduated in Biochemistry last year and my boyfriend in Philosophy a few years before, which makes this all the wilder I guess.

I tried to gently point out that colors exist as part of the visible spectrum of light, so unless he was about to discover some new wavelength, this might not be possible. But he waved me off, calling me “close-minded” and saying he was “enlightened in a way you’ll never be”

At first, I just nodded and let him ramble about his “vision.” But then he told me he needed funding to start his “research.” Specifically, he wanted me to give him $4,000 so he could buy “supplies,” including “advanced art tools,” a lab coat (because apparently, scientists wear them, so it would make him “feel smarter”), and—wait for it—a trip to the desert because he thinks the “pure sunlight” there will inspire him.

I told him absolutely not. I’m saving for grad school, and even if I weren’t, I’m not dropping thousands of dollars on his… whatever this is. He got mad, saying I didn’t believe in him or his “potential to revolutionize human perception.” He even accused me of being jealous that he had a “world-changing idea” and I didn’t. It got really heated and he ended up saying a lot of things about using my card as he knew the details anyway. For reference he’s been unemployed for a while now, whilst I’ve got a regular job. I ended up saying some things I do regret, but a lot of it was retaliation.

Now he’s sulking and telling everyone I’m “unsupportive” and “afraid of innovation.” His friends are backing him up, saying I should be encouraging his creativity instead of “crushing his dreams.” AITA for refusing to fund his quest to invent a new color?

EDIT: In terms of drugs we smoke weed occasionally but haven’t in the past few weeks, I’ve never seen him do any other drugs nor have I found any in the house. So I don’t know if I can really blame this on a bad trip

SECOND EDIT: Thankyou guys for all the advice, I’ve moved the majority of my money into my second bank account for now which I’m pretty sure he doesn’t have access to. In terms of his mental health I’m not in the habit of sharing his personal history online but seeing all your comments I do agree that this might be a mental health issue and I’m going to attempt to approach him with the idea of a consultation tomorrow, if anyone has any advice on that please let me know as I don’t want it to come across as insulting, I know he was down after his job but the comments have got me more worried about more serious illnesses that he may have.