They're actually not *quite* ready to to start testing anything. Monster is currently under a non-compete contract with Coca-Cola that prevents the brand from introducing any non-energy drinks. But come 2020, everything's fair game. And Monster "has its sights on hard seltzers, malt beverages, and spirits," the Journal continued.
We've got at least another year wait until Monster begins testing the new booze and weed beverages, but sounds like they are indeed coming.