Who is chained to a rock to be sacraficed to the sea monster?

Andromeda is the character who is chained to a rock to be sacrificed to a sea monster in Greek mythology. This punishment was a result of her mother, Cassiopeia, boasting that Andromeda was more beautiful than the Nereids, angering the sea god Poseidon. To save her kingdom, Andromeda was offered as a sacrifice, but she was ultimately rescued by the hero Perseus.