i'd take special care of that one, it could end up being a cool cross, you could stabilize it, and have your own pepper. or, they could've accidentally mixed up a seed. or, like you say, it could be a mutation, but i think that is the least likely possibility, but maybe not impossible. anyway, when you get some pods let us know what they are like. if it's something new and exciting, or even simply delicious and hot, then i would trade you for some seeds no doubt. peace and happy growing