system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do humans, or other animals too, get blisters?
gpt
There's not a reason. It just happens that the outermost layer of skin, called epidermis, becomes "unglued" from the lower layer. The liquid that forms is just intersticial fluid - mostly water - that is normally held in place by the epidermis.