No, but it might be personification. It’s hard to tell without a complete sentence or (even better) that sentence in its whole context/paragraph.
Yes, "a frog singing at Carnegie Hall" is an example of a metaphor. Metaphors are figures of speech that compare two unrelated things, implying a similarity or likeness between them. In this case, the metaphor suggests that the act of a frog singing at Carnegie Hall represents something unexpected or unlikely to happen, emphasizing the idea of an extraordinary or out-of-place event.
