The speaker is hurt and angry after realizing that someone valued them only for surface things. The opening question, "Is that all I was?", sounds raw, almost disbelieving, and the word "trophy" shows how it felt to be shown off rather than known. The speaker then pushes back by listing what they really are: deep like the oceans, tough like the mountains, explosive like a supernova, and warm enough to melt icecaps. These images are huge and powerful, which makes the speaker's sense of self feel vast.
The ending is a sharp drop. After all that grandeur, the other person only cared about a hair product. The tiny, ordinary detail about coconut-scented hair makes their shallowness look almost absurd. The mood is wounded but defiant, with a hint of bitter humor. The speaker isn't begging to be understood; they're declaring their worth, even though the other person never bothered to look.