U.S. Securities and Exchange Commission Chair Gary Gensler today wished Bitcoin a happy birthday by using Halloween to poke fun at the cryptocurrency's creator.

In a Tuesday Twitter post, the top regulator also told crypto companies to comply with securities laws.

Fifteen years ago, the pseudonymous Satoshi Nakamoto published the Bitcoin white paper, Bitcoin: A Peer-to-Peer Electronic Cash System. The paper, released online on October 31, 2008, penned a plan for anyone to make payments "without going through a financial institution."

Gensler wrote: "If Satoshi Nakamoto went as Satoshi Nakamoto for Halloween, would we be able to tell?"

He added: "Happy 15th anniversary to Satoshi's famous white paper that started crypto. Any crypto companies that are tricking investors should start treating them to compliance with the securities laws."

Under Gensler's watch, the SEC has cracked down on the digital asset industry like never before, suing major crypto companies like Binance, Coinbase, and Kraken.

The top regulator's biggest gripe with the industry is that many companies are selling coins and tokens that are allegedly unregistered securities.

But crypto bigwigs and lawmakers have criticized Gensler for not being clear enough with the rules. They argue that he has regulated by enforcement and is driving innovation overseas.

Gensler has responded by saying that that the rules are already clear enough.

"They're called the securities regulation, and so there are disclosure regulations for when somebody tries to raise money from the public," the SEC chair told lawmakers back in March.

He has also argued that in the U.S. "we don't need more digital currency," and that the industry is "built on noncompliance."