Half-Life Alyx armored headcrab keyring. The thing is lethal (as the disgusting-adorable thing it's based on:D).
I have also included a body without ...a keyring attached if you wanted to print just the articulated crab,
The ball joints ARE NOT STIFF - the thing was designed to be loose and dangly.
The model is best printed on SLS and/or MJF technologies since the model would require a lot of supports otherwise.
I would recommend this printing service for cheapest SLS/MJF out there and what I have used to print my keyring in the photos: https://3dprintdirect.co.uk/
ENJOY!