I'm 29 and I think this is an 80's movie. All I remember is a boy, him riding a bike, I think he went to get ice cream. He goes to some other place, maybe a dream, and there is a castle with a dungeon surrounded by water. In the dungeon there are these blob like creatures that are bad. At the end of the movie I remember the ice cream was melted. This is what I remember, but I could be wrong... Any possible movie suggestions? Thanks!