I am looking for a high risk and high reward stock

$Tesla(TSLA.US)$ $Amazon(AMZN.US)$ I am almost done with my end of year stock shopping. I am looking for a couple more high risk and high reward plays. I have a well funded 401k and core portfolio compromised of ETFs and blue chips. I am specifically looking for a company carrying a good amount of risk that could blow up over the next year or two.

Any recommendations welcome.