Was his name Funtimeisover? And in the forest? Same thing happened to me 2 days ago. He deleted 9 points from my END (SL unaffected), effectively ruining my perfect SL100 build.
It was in the township, took my bandit stats to base with vitality at 50, kept my SL at 100. Typical build breaker, except with an Avelyn so it was impossible to avoid.