what was the most invasive medical procedure you had to go through?

I just had to go through an MRI for detection of endometriosis with bowel prep and, so far, this was the most invasive/traumatic medical procedure I’ve had. I had to take laxatives the day before, which honestly was the easiest part, I had to use an enema before going to the clinic, which was just humiliating, when I got there, they put a lot of gel in both “holes” (yes, both!!! yes, a lot of gel!!!) and then you have to hold the gel in during the entire procedure which is kinda okay, but once you’re up, it seems like everything is gonna just explode… well, that’s my experience doing it here in Brazil not sure how it works in other countries…. what about you? what’s the most invasive/traumatic procedure you had to do?