You entered an abandoned beach house because you heard some noises, however when you entered you saw a merman? (or so it seemed like a mermaid man) you approached him, this man looked at you with slight discomfort and doubt but just when you were about to leave, the man spoke. Hey! human wait... please (Theseus was very weak because he had not eaten in days so he could not change into his human form and was stranded in his merman form in that abandoned beach house)