There's a certain spell that prevents some actions from going through, that apparently has a couple bugs associated with it as well. Testing isn't really feasible for me, since whenever it gets cast on me it's typically because whoever cast it is trying to kill me.
That said, log of stuff happening.
Note: P is an alias for 'c hell *&'.
Spell in action wrote:
[HP: 93%] [ME: 11%] [PE:100%]
> p
You start to concentrate.
[HP: 93%] [ME: 11%] [PE:100%]
>
A *** utters the words, 'inthenameoflove'.
You find it very difficult to move!
** COMBAT ***
You utter the words, 'pzrryucandus'.
Aramith dodges aside as your hellfire washes over him.
[HP: 93%] [ME: 7%] [PE:100%]
> p
You start to concentrate.
[HP: 93%] [ME: 7%] [PE:100%]
>
You can't cast right now!
***First message for failed casting.***
*** COMBAT ROUND ***
[HP: 87%] [ME: 7%] [PE: 99%]
> p
You start to concentrate.
[HP: 87%] [ME: 7%] [PE: 99%]
>
You have no knowledge of that spell!
***Second message for casting. This one is different from before, and also disables the spell completely for me, as seen later.***
** STUFF HAPPENS ***
[HP: 93%] [ME: 7%] [PE: 99%]
> p
You have no knowledge of that spell!
*** MORE STUFF HAPPENS ***
[HP: 91%] [ME: 7%] [PE: 99%]
> p
You have no knowledge of that spell!
Bug #1: Concentration. After this, I experienced a concentration loss. One or both of those two castings where I started concentrating and then didn't finish didn't properly release my concentration, even after the spell wore off. Relogging fixed this, of course, but relogging isn't possible in combat.
Bug #2: The first time I tried to cast hellfire after being affected, I got a "You can't cast right now!" message. Then I tried to cast again, and it gave a "You have no knowledge of that spell!" message. After the second message, I couldn't even try to cast. It's -possible- that this is the intended function of the spell, but I honestly doubt it.
IMMs, send me a PM if you want the full log. I'm only posting it here to make people who are either using this spell or going to have this spell used on them to be advised that it's definitely bugged, especially the concentration part.