Gymnasts are great at keeping this. Humpty-dumpty... not so much.

I can catch fish, or people's attention. Use me to fasten things, or hang things on. Sometimes I can pack quite a punch, or be an earworm, stuck in your head for a month.

My letters can form Lap rest Lets rap Pal rest Last rep Platers

I lock a door without a key. Slide and twist is all there is to me. Change my first and: - be a bunch of cookies - crawl out of an egg - mend a tear - tell the time

I'm heard by ears, yet soft as can be, A secret shared, between you and me, In shadows dark, or quiet night, I vanish quick, without a sight.