Pissorf'ing a monster into another monster results in sligthly less then 50% damage. Don't remember which was the exact case, but i think if the damage would be an even number it gets rounded down to the next odd number.
Gorgon has a funny interaction with being slowed due to the death gaze. If the death gaze would kill the monster it overrides being slowed and you kill the monster without that it attacks you. This worked at the end of the better, but i would think this still works.
Damage reduction gets applied before resistance. Other way around would be better for the player and in DD the player never gets favoured