Mark Zuckerberg's first tweet in over a decade is playful jab at Elon Musk's Twitter

Mark Zuckerberg's new "Twitter killer" app Threads has officially arrived. And the CEO of its parent company Meta took no time to use it as an opportunity to take a jab at the social media platform owned by his business rival Elon Musk. 

Zuckerberg hadn't tweeted since January 18, 2012, at which time he asked people to "tell your congressmen you want them to be pro-internet." But on Wednesday, as soon as Threads launched, he posted a popular Spider-Man meme in which two identical Spidermen are pointing at each other. 

He didn't include a caption – but no words were needed.