Okay, so, I remember watching this movie on a tape cassete (I think you call them VHS?). Cartoon. I’m rpetty sure it begins with a giant walkignt hrough a street at night, with a suitcase. He might have been doing something with stardust? I think he’s an alchemist or magician. He kidnaps a boy, or the boy falls into his suitcase somehow. The boy had red hair and round glasses (I think).
The movie then carries on in the Giants cave. I’m not sure about what else happens. I saw this three or four times in several places, maybe around 2006-2007 (I could be wrong).