Touch of death
The touch of death is a monster spell cast by powerful spell-casting monsters (of level 21 or higher) in the game, such as arch-liches and the Wizard of Yendor. It has no effect if you are magic resistant or hallucinating, or polymorphed into an undead monster or a demon; it can otherwise fail on a (13 in monster's level) chance. If the spell succeeds, as the name suggests, you die instantly.
Death's "deadly touch"
The Rider known as Death has a "deadly touch" as its sole attack. This touch is different from the "touch of death" possessed by some non-Rider monsters in several ways. Unfortunately, the source code confuses the two attacks, often calling Death's attack a "touch of death" as well.
If you are undead, and Death attacks you, you see the message "Was that the touch of death?" and the attack does ordinary physical damage only. Otherwise, the following effects may appear:
|15%||As below if magic resistant; else no special message||If you have magic resistance, this effect is the same as the one below. Otherwise, you die instantly.|
|60%||"You feel your life force draining away..."||Does physical damage and also reduces maximum hit points.|
|25%||"Lucky for you, it didn't work!"||No effect.|