Well, as someone else already posted, syphon bullets can make your max health negative and also make your current hp flicker from 0 to 1.
If you pick up a survival perk while your health is at 0, you actually become immortal for the duration of the perk.
Here's a video of it (uploaded to youtube because the file is too big):
This is easily reproducible, though unlikely to happen in a real match.
If you pick up a survival perk while your health is at 0, you actually become immortal for the duration of the perk.
Here's a video of it (uploaded to youtube because the file is too big):
This is easily reproducible, though unlikely to happen in a real match.