Photo-sharing app Instagram has removed millions of accounts believed to be posting spam, angering many legitimate users.
People who lost a lot of followers criticised the action, dubbing it the "Instagram Rapture".
Like its parent company Facebook, Instagram routinely removes accounts to limit spam and prevent users buying followers to appear more popular.
Rapper Akon reportedly lost 56% of his followers in the cull.
Figures collated by developer Zach Allia - not affiliated to Instagram - totted up the impact of the purge on the site's top 100 accounts.
The big losers were Justin Bieber (minus 3,538,228 followers), and an online marketing specialist called Wellington Campos, which lost 3,284,304 followers overnight.
One account, chiragchirag78, lost 99% of his followers - 3,660,460 - before he himself was deleted.
Instagram's own account on the site lost 18,880,211 followers overnight.
Instagram had warned its users that the deletion was coming in a blog post earlier this month.
"We've been deactivating spammy accounts from Instagram on an ongoing basis to improve your experience," wrote chief executive and founder Kevin Systrom.
"As part of this effort, we will be deleting these accounts forever, so they will no longer be included in follower counts. This means that some of you will see a change in your follower count."
Reacting to the purge, many of the site's users directed harsh words at Instagram - while others saw the lighter side.
Rapper Ma$e, who lost more than a million followers, deleted his account after he was accused of paying for more followers, while video blogger Jamie Curry tweeted: "I lost 30k followers on instagram omg."
Matt McGorry, an actor who has starred in prison drama Orange is the New Black, wrote: "There may be 545k Instagram followers left but my 11k spam followers that disappeared took a piece of my heart with them.
"I'll honour the memory of each of my 11k spam Instagram followers that I lost with the lighting of candles. Well, one candle. I only have one."
