What is Ha-un?
1.
1. In live or computer RPGs, the principal material component of equipment used by your opponents to reduce you to a thick yellow smear with no effort or risk, especially those items/gadgets which cheerfully violate all of the game rules YOU have to abide by.
2. An item or power you will never, ever be allowed to get your hands on it because it's too powerful and serves only as a plot device or some referee's sadistic whims.
Named for its chemical composition. HA (handwavium) + UN (unobtanium)
Their "Guns of Vaporizing Players +15" ran on HA-UN batteries and so were useless to us.
The GM equipped all of the monsters with HA-UN armor because we didn't bring snacks.
