Why is there a random arm taking over the X composer?

X is apparently experimenting with a strange tactic to get users to pay to boost their posts. People are starting to see a brief animation of an arm taking over the post composer in the X app. The arm appears only briefly and points at the "promote" button, according to multiple posts and screenshots from users.

The change doesn't seem to have hit all accounts just yet. The "promote" button appears in the composer view for accounts with a paid subscription to X Premium. The randomness of the new animation, though, is confusing X users. Is the company that desperate for promoted posts? Is it a prank? X hasn't publicly weighed in.

Here I am wanting to post my typical GM post and I get spooked by this animated hand pointing at promoting it... is this some sort of Halloween joke or we going to be forced to ignore it every time we want to post something from here on?

(Try it! That hand just pops out of... pic.twitter.com/KbaVypGqp7

— MartaTrades (@AureaLuma) October 27, 2026

Every PM has basically wanted to point at the button they want users to click, but instead spends time designing subtle nudges.

Kudos to X for just shipping this arm. pic.twitter.com/Fo1PAOzbLq

— aneri (@0xaneri) October 27, 2026

I was about to post a photo of my new iPhone Duo on X and this giant arm came out pointing at the "promote" button — what's this all about? pic.twitter.com/mcKPj3ZdI9

— Casey (@casey_lau) October 27, 2026

The appearance of the mystery arm also roughly coincides with X hiring Peter Sellis, its new head of product. Sellis, who is taking over for Nikita Bier, previously held similar roles at Discord and Snap. And, like Bier, he's known as something of a shitposter. In his post announcing he was joining X, he said that "it's time to make shitposting multiplanetary." It's not clear how an unexplained arm would contribute to that goal, but we do know Elon Musk is a fan of a dramatic, if cringey, entrance.

So while there's been some speculation the hand could be the work of Sellis, he hasn't publicly commented on the arm either. It could also simply be a Halloween-related prank, as Grok has speculated.

"That hand is real—not a glitch or pure Easter egg," Grok told one user. "Lots of users got the same jumpscare today. No official word if it's intentional design or Halloween timing." The bot gave similar replies to other perplexed users.

A representative for X didn't immediately respond to a request for comment on the hand.