2) Position yourself between any monster with a knockback and another monster.
3) Hit the knockback monster.
4) Bug one: notice how the corrosion damage did not apply to the second monster.

5) Bug two: If that second monster has blink, it will blink away. Well, I did not attack it!!! If I pisorf some other monster into the blinking one, it does not blink.I guess it is because it checks for YOUR proximity, instead of the source of the damage.
Two bugs for the price of 1!

video: https://youtu.be/RvQyHYBttv4
This is very sad, because I was hoping to 1-shot bosses this way. You can get self-corrosion to practically unlimited levels. WEYTWUT the minotaur, WEYTWUT the boss, 1 DP, done. So you need 2 DP in total to kill both bosses. Don't even need CYDSTEPP, just be a Fighter + find Badge of Honour.