It turns out that Respawn already has very specific plans when it comes to Halloween in Apex Legends.
Players have found that Leviathan will appear in Apex Legends as part of a seasonal event. Interestingly, they change their appearance to be more spooky.
The circumstances of the return are not yet known, but the appearance of huge creatures has leaked.
It looks really phenomenal. The whole map is really dark. See for yourself:
Halloween will probably start very soon, unfortunately, the exact date is not yet known.