When your gut keeps whispering the same odd idea, stop overruling it and sketch it once.

An idea that keeps returning is information. Your attention is not random, and something in you has already decided that thing is unfinished, so it keeps raising its hand no matter how often you rule it out for being strange or impractical. Overruling it costs more energy than testing it, and it never fully goes away while it is still untried.

Give the recurring one an hour. A single sketch, one verse, one page, with no promise to finish. Either it dies honestly or you find out why it kept coming back.