Does 大怪球 mean anything in Japanese besides the literal translation of large mysterious sphere?

Yes, "大怪球" (dai kai kyuu) can have connotations beyond its literal translation of "large mysterious sphere." In some contexts, it may refer to specific fictional or fantastical elements, such as characters or objects in anime or Video Games. Additionally, it could evoke themes of adventure or the unknown, depending on its usage in cultural contexts. However, it is not a widely recognized term in mainstream Japanese.