Very unsafe-looking receptacle
I searched for this and couldn't find a NEMA code for this outlet (no surprise there!). But in my research it appears that this has been around for a long time, terrible idea as it was. Attached is a pic of a similar outlet that is obviously quite old.  There are actually 3 of them with the same configuration in the pic.  I would rather have made this a comment, than an answer, but pics can't be posted in comments.