The ASUS ROG Phone has multiple USB type C ports, so that it can support accessories that need two of these ports. A Redditor has demonstrated that this feature can be hi-jacked in order to make it appear that the phone can charge itself. However, the effect may be less than authentic.
https://www.notebookcheck.net/Reddit-post-suggests-the-ASUS-ROG-Phone-can-charge-itself.375226.0.html