An array of public companies thought they had found a sort of perpetual motion machine: Use your corporate cash to buy up Bitcoin or other digital tokens and presto, your share price shot up even more than the value of the tokens you bought. It was a playbook invented by Michael Saylor, who transformed his company, Strategy Inc., into a publicly traded Bitcoin holding vehicle. One prominent entrant, SharpLink Gaming Inc., soared over 2,600% in a matter of days as the company said it would pivot from its old work in gaming, and sell shares to buy up lots and lots of Ethereum tokens, with one of Ethereum’s co-founders as the chairman.