Yeah, he really knew what he was doing. Too bad he moved to the other side of the continent a few years ago. (He's in the navy.) I haven't seen nor heard from him in a while.
He would roll to determine whether copper, silver, gold, iron, platinum, mithril, etc would affect the changed PC. He had a chart with percentages, and rolling one number, for instance, might make the lycanthrope harmed / DR passed by Copper, Gold, and Platinum. I chose that example as it actually happened to one of the other players. He eventually gained some control over his form, but to keep himself from flying off (He was a werehawk, one of th types that hunts in the dawn / dusk period and during brighter moonlit nights.) and waking up in odd places he got a strong silver cage for himself (didn't want to hurt himself, just contain himself). It could have been iron, but after having spent several game sessions only able to touch silver coins, he grew to rather like the metal.
Because of the rolls the DM made when he got infected, he was never able to remember what happened, but he was eventually able to learn to force the change to occur and to give some initial direction to its actions. He did not attack his friends, and he was lucky enough to be able to eat raw animal meat instead of being limited to fresh and raw human(oid) meat. Also, because of the roll that determined whether he would / could learn of his curse, for the longest time he was unable to accept any evidence of his curse. He was in an enforced state of denial (requiring a will save to attempt to overcome this each time new evidence was presented to him). It must have taken nearly a half dozen game sessions before his character finally 'realized' the truth of his condition and allowed the group to try to help him. He was infectious, but it could only be passed on to humanoids, and his other form hunted other animals (rats, voles, other birds, sometimes lizards, etc - ie: normal hawk food).
Another was more difficult to deal with. He was 'allergic' (as the DM called it) to silver and iron, and while he was aware of his curse and could recall what he did while in it, he could not control himself. He was a traditional wolf as well, and he tended to attack any fresh meat he could find, although due to the DM's roll his will save to resist attacking team mates and others he wished to avoid was rather easy (something like a DC 8 or 9 as I recall; the DM tended to roll 3d6 and add 2 to the result, for an average of about 12.5). SO he tended to leave the camp and go looking for bandits, goblins, etc to attack. He was (thankfully) non-infectious, as a few got away from him.
Also, there were rolls to determine which phase of the moon resulted in transformation and whether transformation could occur involuntarily if the character suffered extreme damage or a near death experience (ie: succeeding by less than five on a save or die effect or a save vs massive damage).
All in all, it worked rather well for the group. There was some hope: either it was an inconvenience the party could work around (such as caging the first character each night of the full moon), or it could be cured (as eventually occurred with the actual werewolf in the group), or it could be repressed. The campaign was were-centric, and my character also came down with it, but later on he found an amulet that while worn would prevent the transformation. The down side was that it detected as evil, causing all sorts of problems with clerics, etc.
