My nephew was apparently in need of some of his own dress-up clothes so for his 3rd birthday recently, I made him a cape using these fabrics and this tutorial:
It’s totally reversible and the neck closure is done with a little bit of velcro so it’s pretty safe (the velcro comes undone easily so it would be hard to strangle yourself).
Because of the length and the way the seams are tacked down it has a pretty good swing to it, even when one is wearing a bathrobe:
