In Denmark back in the 90s it was pretty normal to give kids (and often adults) nitrous as a sedative at dentists. I had it a dozen of times as a kid, but only

In Denmark back in the 90s it was pretty normal to give kids (and often adults) nitrous as a sedative at dentists. I had it a dozen of times as a kid, but only once did I hallucinate anything. I was awake and fully aware every time, but the one time my dentist voice was very boomy and reverberating and everything was black except for some animals and shapes I saw in multiple rows scrolling left and right and I remember thinking that my dentist was a big frog. I don't know why that one time was so weird out of all the other regular ones, but I know I was still awake and I was addressed and I could reply, but I was still tripping my balls off.