Nasa says just a space rock.

"Is there a danger of this interstellar object hitting Earth?

No. Although the trajectory of the object brings it into the inner solar system, it won’t come close to Earth. As the comet 3I/ATLAS journeys through the solar system, it won’t come closer than 1.6 au (about 150 million miles, or 240 million kilometers) to our planet."

https://science.nasa.gov/solar-system/comet...s-sidebar-nav-3