We don’t know why this cat was hanging from the shower curtain – while his human was taking a shower – but we could take a wild guess. He was napping inside the shower, where he’s not supposed to be, where his human wanted to take a shower. As he heard his footsteps approaching, he jumped on the curtain in an attempt to hide.
Another option is that this cat loves his human so much, he couldn’t stay away from his for even ten minutes. When he was taking a shower, the cat obviously couldn’t join him there, for obvious reasons, so he did the next best thing. Perhaps the most amusing part about this photo, however, is the other cat curiously looking at this strange situation.