I thought I'd gain some more experience in 3D modeling and try and recreate a common object. I recreated the Scrub Daddy sponge and miniaturized it and made a keychain out of it. 

This is made in 2 parts which secure together using 1.75 mm filament. It should be a snug fit but if its too loose you can use glue to secure it in place. A significant elephant's foot will probably make the holes too tight so be aware of that too.