The Yam Yam is one of the most exciting creatures. When it explodes
(by dropping a rock on it, for example), it can turn to nine new
elements. Further exploding Yam Yams can turn to other elements, up
to eight different sets of new elements.

Sometimes the last emerald you are looking for to finish the level
is hidden in a Yam Yam! But be careful: Yam Yams will eat all diamonds
in their way!
