You see a soul floating around a tombstone acting suspicious. To be fair, if a soul is going to be anywhere, a tombstone is probably high up on the list, but this one seems like it's doing something weird.
You sneak around the tombstone to see what this suspicious soul is doing, and you realize it's pretending to kayak (かい). The soul is sitting behind the tombstone, in a small kayak, moving its arms like it's rowing through water.
Even more suspicious, the soul seems to be wearing a kevlar (け) vest. Considering the soul is already dead, this doesn't seem like something it will need.