A fun and rewarding way to mistreat your film is to double expose a roll with yourself or a friend shooting the first layer normal and the second layer as redscale. Just watch the colors explode. If you want to further punish your film then give it the ol' x-pro treatment.
Using a roll of Lomo X-Pro slide film I shot the first layer at 250Roct which is about 200iso then after carefully rewinding it without it going back into the canister I cut off the leader and taped it to be wound into another canister upside down. After cutting a new leader I loaded it back into my camera and shot the second layer as redscale at the same settings. I then took the finished roll into the lab and had it x-proed for good measure. The results were mind blowing colors and crazy saturation. On one end of the spectrum were wild blues and on the other were sharp and fiery yellows and oranges.
With slide film the redscale effect generally is more sensitive because the emulsion layers aren’t as thick and foggy. It is wise to under develop that layer by a couple stops minimum. I unfortunately didn’t have the option of shooting any more than 200iso so a few of the pictures were totally overtaken with redscaled hues. A color negative film would be less sensitive and provide a toned down redscale effect if that was your aim, but then you have to realize you won’t get those wild x-pro colors. Make a film choice and a game plan and get out there and do it!!! You won’t be disappointed.