I think one of the best things about Japan is the fun way all sorts of new flavours are made for things like soft ice cream, KitKats, soft drinks, etc.
Apple was a pretty good soft ice cream flavour for me. Anata ha?
I once had sweet potato and lavender - not together. The sweet potato was actually kind of good. The lavender was okay as a novelty, but odd. But the strangest flavor I heard of but never got a chance to try is something call charcoal flavor. Yeah, weird but I wish I could had tried it just to have the bragging rights.