Au in which Danny is a biologist teacher at Gotham academy. He is the best at his unit on the human body as he will just turn his skin translucent and just start pointing at the different organs.
What do you mean his heart that we can clearly see isn’t beating?
Only in Gotham do teachers remove their skin to teach about the human body and have none of the students blink an eye.
Bonus point if all the batkids have Danny as their teacher and haven't flinched or thought about reporting it to Bruce because it's not important.
It was when Jon was answering Damians about the difference between his x-ray vision and vision through transparent skin while eating Alfred's cookies in the presence of Bruce (who stole a cookie in the process) that Bruce finally learned about the biology teacher with skin that can make it become as transparent as glass