A soft-boiled egg cracker.We ordered it from Amazon because it was highly rated and recommended as the best soft-boiled egg cracker on the market (I barely tolerate soft-boiled eggs, but Ms Eclectic enjoys them). When we got it, we couldn't figure out how it works. We actually had to YouTube it.
Simple. You set the big end at the bottom over the egg, lift the ball along the pole to a knob at the top, and let it drop. It cracks the egg nicely.
I ordered one for my nephew, who complained that it didn't remove the shell. It just cracks the shell in a nice, convenient circle.
I've seen other devices on AliExpress that do something similar.