If you set a lightning bolt to plsm, it makes plsm that dies to dstw (then wtrv).
12Me21:
This is because PLSM with ctype FIRE will turn into water (this is used in the HYGN+OXYG+FIRE->WATR reaction)
I think you are mistaken... setting tmp of fire or plsm to 3 makes those elements turn into watr. I just tried it.
Ok, that makes more sense... Anyway, the reason that this happens when you change LIGH to PLSM is because parts of LIGH have tmp 3