Vitalik Buterin, co-creator of the crypto network Ethereum, donated more than $1 billion on Wednesday to a relief fund to combat the spread of Covid-19 in India.

At least, it was $1 billion when he made the donation—in a cryptocurrency that few had heard of and whose value plunged right after news of the donation spread.

In more conventional terms, the donation would rank among the philanthropy’s biggest strokes. But little is conventional: The currency, Shiba Inu coin, has been around for less than a year, and is one of a bevy of alternative cryptocurrencies that have exploded in popularity and price in recent months. Its value changes wildly by the hour. Unlike with cash, or even bitcoin, it is hard to use Shiba Inu coin to buy things.

The most prominent alt-coin is dogecoin, created as a joke in the fad for bitcoin doppelgängers. Shiba Inu is a joke on a joke, named for the dog breed that is the dogecoin’s mascot.

The donation surfaced in publicly available transaction records, which show that an account associated with Mr. Buterin sent some 50.7 trillion Shiba Inu coin to an account associated with the India Covid-Crypto Relief Fund. The transfer originated from an account that Mr. Buterin, in a 2018 post on his verified Twitter account, said was his.