Does the video show a huge reptile in Australia?

The truth 

The circulating post is fake. The video in question was created using an AI tool called Gen-3 Alpha. Timmy, the CEO of Runway, a company conducting AI research, shared the video on his X account on June 20th. He confirmed that the video is a result of the company's work using Gen-3 Alpha."

 

What do you know about Arthropleura?

Arthropleura is one of the largest extinct invertebrates (arthropods) and lived around 326 million years ago. Fossilized remains were accidentally found on the northern England's Northumberland county shore. Researchers believe Arthropleura had at least 32 legs, possibly up to 64 legs.