I lived with someone in his 20's and 30's who behaved exactly like that. I often WISHED I could have just spanked his bottom red.
Like Katz, I'm sending Curtis from the table. I will let him know that food has been provided for him, INCLUDING tartar sauce, which he is refusing, and that he won't starve to death overnight regardless. He can't be that hungry if he's making this much fuss.
After the rest of us have finished our dinner, and he's had time to calm down we'll talk. That talk will NOT result, however, in my running out to buy a bottle of Heinz Tartar Sauce. Whether Curtis gets spanked, goes to bed hungry, or gets a PB&J will depend a lot on his attitude when we talk.
When my son was 8, we visited Toronto, and one night had dinner at a very nice Italian restaurant. He ordered spaghetti with butter, and received homemade tagliatelli, which he refused to touch. I explained to him that all pasta came from the same dough and was then cut into different shapes. He'd have none of it, and we ended up stopping at a McDonald's drive through on the way back to our hotel (he didn't throw a fit--just wouldn't eat it).
On arrival home (not hotel), we made homemade pasta. I rolled out a strip of pasta, then very ostentatiously cut it in half for him. The first half I put through "spaghetti" cutters; the second through "tagliatelli" ones. "See, it's exactly the same thing. One is just cut smaller than the other." "Yeah, I see, it's exactly the same." "So, you're gonna eat it, right?" "No way!"
A few months later he asked when we were going to make spaghetti again. "When you'll eat what we make". We'd still never made homemade pasta again when I filed for divorce.