Two Details From The Shape Of Water Its Star Sally Hawkins Actually Wrote

However, another viable reading of the film’s ending is that the creature turns her scars into gills (rather than restoring gills that may have previously been there) and grants her a new home in the water.

That said, one thing that Guillermo del Toro didn’t explicitly explain in his conversation with Deadline is how Elisa’s gills factor into the story.

The film makes it clear that Elisa was found near water as a baby, which lends credence to the possible theory that she is actually from the ocean, just like the creature.