Bought £22 of Ethereum Classic on Coinbase as an experiment back in December 2018. All it did was go down, then back up to the same value in February 2020, back down to as low as £8, and now going back up to the £19 mark.

Not sure how much of a "no-brainer" of an investment this is, but luckily didn't fall for the hype and put in any more than a nominal amount to play with...