question: what if nightfall|eclipse enter the field before this card? did you really mean it to be played first before nightfall|eclipse?
might as well reword into this if not:
"If affected by Nightfall or Eclipse, turn into a Werewolf|Wolf"
answer: permanently turn it into werewolf or course
question: what's the different between my description and yours?
With your wording, if a Nightfall|Eclipse is already in play, Lucius would not turn into a werewolf, since "Nightfall or Eclipse come in play" already happened, and Lucius wasn't there.
The other wording works even if Nightfall|Eclipse is already in play.
Other than that: we already have a Werewolf card
, so i think you should change the name, like "Werebeast" or something like that.