What does the sour tower do in viva pinata

You must have heard of the sour pinatas?
Well say you have a sour crocodile and you buy a part of the sour tower which is the crocodile. It will keep the pinata out.
** I must say don't waste your chocolate coins on such a thing and try to tame the sour pinata. So once you reach level 18 you will have enough chocolate coinc to get digger and get a dragonache.