Is warming up sushi a thing?

My town is very small and we have this “Asian Fusion” place that well, seems to serve everything from previously frozen chicken nuggets to sushi, ramen, burgers and pizza. A lot of people have been giving it excellent ratings for their sushi but again I’m in a small town and I honestly don’t think most of the people here have had sushi other than this restaurant. So I decided to give it try myself. I ordered a bowl of ramen that was pretty bad actually. It was as if someone made a good bowl of ramen and then drained out 80% of the broth and replaced it with canned Campbell’s Chicken broth and water. Something was also off about the noodles because they were gummy. But I’m here to talk about the sushi. So this place doesn’t have any nigiri options and when I asked, the waitress said “it’s good rolls!” and pointed to the menu at a few things as if I had asked for recommendations. There were about 50 different rolls listed but most of them appeared to be the same plus or minus an ingredient and it was the kind of place that put lots of various sauces on top of every roll so I could only imagine they all would taste very similar(they did). HOWEVER, the worst part was that they served what I ordered to me on a hot stone slab. They brought it old holding it with wet towels and placed it in front of me and warned me it was hot and it was. Then they brought out the sushi on another place and the waitress literally grabbed the rolls with two hands(she had clear plastic gloves on) and placed them on the hot slab where they all started to sizzle and you could hear some of the rice make a popping sound. I had no idea wtf was going on or why they were doing this and I went along with it thinking maybe it’s something new or like their own signature way to serve it. As far as the taste of the sushi goes, I have had better grocery store sushi and that’s not an exaggeration. But what made everything so much worse, aside from the bottom of every piece being crunchy from the heat, is that the heat also warmed every piece all the way through. It was still raw, but it was warm like it had sat in the sun and that just made the whole experience severely off-putting. I could only eat about 1 and a half rolls worth out of the 5 rolls I ordered and I asked if anyone spoke English. This guy comes out and speaks slightly better English than the waitress and I asked why they put it on the hot slab and he said “traditional traditional!” “It’s good rolls!” “you like? Thank you!” and at that point I just gave up and asked for the rest to go, which I then deposited in into the trash bin on the way to my Jeep. Then I googled everything I could find about what had just happened and I can’t really find anything about it. I can’t even find people that commented and reviewed this restaurant, complaining about it or pointing out that it was a weird thing to do. I’m seriously considering going back but only to get pictures and video of what’s going on at this place. This is in Northern Indiana by the way. Has anyone here ran into this sort of thing or heard about it and can you explain the origins?

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EDIT: I did find this in my search “hot rock sushi” but this is sashimi that they’re cooking on a hot rock themselves, similar to how beef is served in Japan and the customer can cook it on a grill/rock. It’s not actual rolls of sushi being scorched. [https://johncollings.com/tag/hot-rock-sushi/](https://johncollings.com/tag/hot-rock-sushi/)

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EDIT 2: If you find yourself believing that the above is “TLDR”, you might consider spending more time reading and less time looking at pictures of sushi. Just saying. Thanks for any actual help.