The Chinese have designed and developed a gas-powered roller blade.
With a 25cc engine attached to the right boot along with a small fuel tank, they carry the wearer along at up to 20mph. They are controlled using a handheld throttle and can reach maximum speed within seconds. But there is no brake. The only way of stopping is a shut-off button which acts like an emergency stop, throwing the skater forward at speed. If they were legal they would be classed as a motorised vehicle and the user would need a driving licence, insurance and L-plates [plates on skates? -Edit.].
It sounds like the perfect black market gift for that special person in your life who loves danger but has already been to a Thai cathouse and who wants to look like a pussy but already has a Vespa. And look! It's already available in Florida! Thanks Craigslist!