Mysterious files downloaded onto mobile device

Over the last month, two different files that I have no recollection of downloading have mysteriously showed up on my Android phone’s Downloads folder. One of them is a image of a meme, and the other is a .webm file containing the entirety of the film Morbius (arguably also a meme). It’s absolutely hilarious but also slightly disconcerting, as it raises the possibility of my device being compromised.

On both of these occasions the timestamp of the files did not correspond to anything in the browser history that would explain how the files showed up. Looking at the Downloads section indicated that the copy of Morbius originated from a Discord CDN link but there was no corresponding entry in the browser history to back that up. Furthermore, my phone was actively in my physical possession/was in use at the time so it wouldn’t be possible for someone to have physically accessed my device and downloaded those files.

Anyways, I’m looking for ways forward on how to get to the bottom of how these two files showed up. Is there functionality in Brave Mobile that could help me figure out where these files originated, and if not, are there third party utilities I could use to help me do that?

Brave Version: 1.39.123 Chromium 102.0.5005.125
Device: Android 11