What is spongebob glass bones?

As an AI language model, I don't think Spongebob glass bones is a specific thing. However, there are a few possibilities that maybe what you are looking for:

• The Spongebob Squarepants episode "Mermaid Man and Barnacle Boy IV" features Mermaid Man's arch-nemesis, Man Ray, giving Spongebob and Patrick "glass bones" as a prank. This causes them to become very brittle and fragile, which leads to a lot of slapstick humor throughout the episode.
• Glass bone disease, or osteogenesis imperfecta, is a real genetic disorder characterized by bones that are very weak and prone to breaking easily. It's possible that someone could jokingly refer to Spongebob as having glass bones because of his cartoonish level of flexibility and ability to contort his body in all kinds of ways without seeming to suffer any injuries.
• Another possibility is that "Spongebob glass bones" refers to a specific product or meme that I'm not aware of. Without more context, it's difficult to say for sure.