Space

Not sure if anyone has run the exact numbers as to what would it look like precisely, but my initial guess is "less than pleasant

Hah!

Indeed, circumstances matter, but the process would be not as dramatic as often portrayed. The instant boiling blood on contact with the vacuum is a myth. It wouldn't be pleasant, but not very violent.

After all, the pressure difference is about one bar. Deep sea structural collapse is way more dramatic than the same thing happening in space.