This is a hammer toy I originally printed for my infant son and have since printed for many other kids. I print the handle from brown PLA, and the head from silver. 

Included are three different head models to choose from, and the option for rattle beads to go inside. Also note the hole in the handle shaft for a retention loop - necessary for pretending your baby is Thor or attaching a string to hang on the wall.

For legal reasons, don't give this to a kid. They may like it and chew on the plastic or something. Full disclosure that my son has three or four of these and loves them and chews them all the time with no ill effects.