Ohhhh Gucci. Geez, he really likes those elastics hey? Missy gobbled one up before too, but it was just one of the teeny ones. I hate when they do that...just as you're reaching to take something away from them, they swallow it!
I personally wouldn't induce vomiting unless it causes him some issues. It will likely pass tomorrow.
Gucci, give your poor Mommy a break. Quit eating the elastics