King of the Dead
Interesting. I think I must have used the rules for the Shock trap just above it.
Shock: The trap discharges a powerful bolt of electricity into the Hero who set off the trap. Roll 5 damage dice for effect. If the Hero is wearing any metal armor (for example, chain, plate or mithril), roll 10 damage dice.
I can't remember for sure though. It's been years.
I also have a note here next to the Choke spell trap to see Terror in the Dark page 77.
Shifting over there is a rules revision:
CHOKE TRAP (Rules Revision)
With a Choke trap, the effect on a character who triggers it is that they may only move one square per turn (as determined by the player). At the end of the turn, the character is allowed to roll a D12. If he rolls below his Toughness score, the character lives. If the D12 roll is above the character's Toughness, the character dies. A Choke trap can be evaded entirely by a special magical protection such as a Ring of Magic Protection. A Fate Point can be expended to negate the effects of a Choke trap. The effects of a Choke spell (as opposed to a trap) are unchanged from the those given on page 55 of the Advanced Heroquest rulebook.