Apparently this is pretty common, but I've never seen it until now! Viola...a magical set of Sims cosplays!
The best part of this is that making the Sims Plumbob (yes, that's what little green do-hickey is called) is really actually quite easy!!
Or, if you want to get a little fancier and make one that is really, really sparkly, try this tutorial. Either way, I know I'm doing this for an easy cosplay someday!! I just gotta! Or, maybe, Halloween.