Ads for the crypto token Floki Inu, which ran on London’s public transport network last fall, breached UK advertising standards, according to an investigation by the advertising watchdog.

The Advertising Standards Authority said the adverts, which featured the slogan ‘Missed Doge? Get Floki” and a cartoon dog mascot “tapped consumer fears of missing out. . . trivialized cryptocurrency investing and took advantage of consumer inexperience or credulity.”

The Floki Inu ad campaign, named after Elon Musk’s pet dog, has become a flashpoint for objections to the widespread advertising of crypto tokens and exchanges in the UK, with several London lawmakers calling for a ban on public transport advertisements.

In a response published by the ASA, Floki Inu said he had included a risk warning and checked the adverts with the Committee of Advertising Practice, the organization responsible for writing UK advertising rules, and had been informed that they were up to standard.

Floki said he did “while [its] power to comply” with advertising rules at the time, and that the ASA was unfairly applying changes to its guidelines retrospectively.

Publicizing crypto investments has become a key focus for regulators in jurisdictions around the world, as watchdogs worry about the risk of consumers being tempted into risky coins and losing money. Spain, Italy and Singapore have all tightened standards on crypto promotions this year.

The ASA also took crypto exchanges to task for what the agency called “widespread” problems with misleading and irresponsible advertising, reprimanding seven companies in December, including eToro and Coinbase.

Crypto ads had proliferated in part because they were subject to less stringent rules than promotions for regulated financial products such as stocks and funds.

The UK Treasury said in January that it would seek to change the law to give the Financial Conduct Authority oversight over most cryptocurrency promotions and bring them “up to the same high standards as other financial promotions.” such as stocks, shares and insurance products are required to comply.

Floki Inu particularly attracted attention as the coin’s promoter refused to identify himself while soliciting investment from the public. The token’s backers funded their ad campaign with a 4% “marketing fee” on buyers, an approach other coins have taken as well.

The ASA said: “We have corresponded with attorneys for Floki Inu, who have confirmed that the advertiser is based in Georgia (the US state).” The regulator added that it told Floki not to repeat the ads, but his reprimand does not result in any sanction for the crypto group.