Do any of you use this rule?
(Liber Mutatis p18/ P.54 GM's guide ):
GM Invocation [Corruption]
Over the course of play, the GM has the option to “manifest” or
“invoke” a character’s corruption, weaving into the story that the
exposure to corruption or taint is rearing its head. The GM narrates
how the corruption is manifesting, which makes the upcoming
task more challenging. The corruption might manifest as an
overwhelming sense of temptation, painful cramps, or whispered
daemonic voices only the character can hear.
Mechanically speaking, before a player performs an action, the GM
may take one of the character’s corruption points and replace it
with a purple challenge die that gets added to the task’s dice pool.
The corruption token is returned to the general supply [lowering the character's current corruption point total]. No more
than one corruption may be invoked in this manner per check.