Love this game. Found this during my first playthrough. If you stab the tissue box out from the crab before it pops up, the physics of the game get real freaky. I think the tissue hitbox is still hanging around for some reason. When you pull into your shell you start getting pushed upwards.
The actual effects seem kind of random. Sometimes you get big launches when you release and sometimes you only lift a foot off the ground. Sometimes pulling out your fishing hook gives you incredible launches, sometimes it propels you into the ground, and sometimes it does nothing. The effect stays between areas but changing your hammer ends the effect, as does your hammer breaking.