Huh, I thought, what a strange way to apologize. I sent the tweet to a fellow reporter. “Oh lol,” she said. “Those are fake Elon accounts.”

I went back to Twitter and clicked through. The account looked almost identical to that of the Real Elon Musk: same picture, same display name. But the handle wasn’t @elonmusk. It was @elomtusk. I’d been duped.

I wasn’t the only one. This fake account is just one of many in a growing ecosystem of scammers lurking in Musk’s mentions. They create nearly identical accounts with handles that are just slightly misspelled, and then attach themselves to the real Musk by directly replying to his tweets. They share links to cryptocurrency giveaways, where they ask unsuspecting users to send them small amounts of cryptocurrency, with promises of an even bigger payout. The more creative ones even enlist fake accounts to respond to them with excitement, urging those around them to join in.

“I sent 1 ETH per instruction in the link you provided and never got anything back,” someone tweeted at the real Musk this week. “What’s going on here? Did I just get scammed?!!”

“I just got scammed last night out of.22 Bitcoin, which is about $1650 USD from a fake Elon Musk account about Bitcoin giveaway,” another tweeted, addressing @TwitterSupport. “How is this fake account allowed to be up for hours last night?”

“Well … I’ll admit I just got scammed,” tweeted another. “This isn’t real. I’ll look like an idiot to warn someone. There are 2 “ll”s in elon. I didn’t even look since it was a reply.”

Musk seems to be a favorite of the scammers, who tend to impersonate high-profile figures—others include President Donald Trump and John McAfee, a bitcoin evangelist and the founder of the eponymous software-security firm. The deception has become so rampant this year that Vitalik Buterin, the co-founder of the cryptocurrency Ethereum, changed his Twitter display name in March to “Vitalik ‘Not giving away ETH’ Buterin.”

The schemes can cost victims significant amounts of money. According to a July report from Kaspersky Lab, the cybersecurity company, these lurker-scammers have conned users out of 21,000 ETH—the currency exchange symbol for Ethereum—or more than $10 million, in the last year.

The account that tricked me this week has since been suspended, and the Blogger page has been removed. But there are many others, and when one gets kicked off, a new one arises. Some remain active for hours or even days. In May, a fraudulent account impersonating Kevin Pham, a cryptocurrency investor, remained online for three days. Wrangling these accounts is like playing a game of Whac-A-Mole, and the moles are winning. “I want to know who is running the Etherium scambots! Mad skillz,” Musk tweeted earlier this month.

Twitter’s rules prohibit impersonating “individuals, groups, or organizations in a manner that is intended to or does mislead, confuse, or deceive others,” and the company has said it’s working on rooting out the fake accounts. “We’re aware of this form of manipulation and are proactively implementing a number of signals to prevent these types of accounts from engaging with others in a deceptive manner,” the company told The Verge in March.