I have found out that frog's tongue may have a use. When you stand beside a wall, it will go through it! You shouldn't make more than 1 tile widht of that wall (in simple tileset like Castle or Carrotus, tilesets like Medivo need to check out yourself), so it will work. With that tongue you can pick up goodies and react with Trigger Zones or Rock Triggers, so that to continue on or gain stuff you have/want to become a frog!

Hmm...that would be a good piece of trivia or a neat trick in a puzzle level, but I doubt it has a huge amount of use. Still, it is one of the things to add to a large list of "neat JJ2 tricks that could be used in the Best Puzzle Level Ever", which I await with bated breath or something.

~ Traft

Well, yeah. Except it doesn't turn on trigger zones.
Rating: Common knowledge (I hope).

It's obvious why that happens. The frog's tongue extends the sprite, and when the sprite, that is masked as a rectangle, rather then in the frog's shape, touches the goodie, it will obviously react. Put a goodie in a wall, and then have Jazz or Spaz push on the wall. Their hands will extend a bit over the wall, and they'll get the goodie.

The sprite's mask that reacts to solid tiles seems to be a square, but the actual sprite is the mask used when collecting things or taking damage. You can also get things behind walls by ducking or shooting.