Gunther is a non-giftable character who runs the Museum. You can always find him inside the Museum between 8:00AM-6:00PM. Upon entering the Museum once you have found a Mineral or Artifact, Gunther will explain to you that someone has stolen the Museum’s collection. Instead of accepting gifts, he only accepts donations to the Museum. After donating 60 items, he will gift you with the Rusty Key.