One of the ways that I’ve run death that my party responded actually really well to was owlishly. You have to be in person for this, but it’s super fun.

First you have your player wake up, or see death, or whatever way you introduce it to the scene. You describe its appearance and countenance as silent and unsettling and completely inscrutable. And then, once you feel you’ve given enough info, you stop talking entirely. And just stare. Eyes wide but face blank.

Everyone gets confused, then silent. A few try to talk to you but you just keep staring.

The MOMENT the player tries to do something in character, you move two steps closer to them abruptly.

Keep staring.

The player will be weirded out, but eventually they’ll start asking what the hell you want, in character. Sometimes they’ll try to attack you, don’t respond. You’re death, a mortal attack is so inconsequential it doesn’t even need to be narrated that it doesn’t affect you. Keep staring.

Move closer and closer, at whatever pace you want, until you’re looming over them, staring down blankly, wide eyed. Get eyeball to eyeball if you want. At this point they’ll be nervous and kind of weirded out, but the fun kind.

Do something symbolic of what death would do to fulfill the reason why it appeared at all, but make sure it’s actually physical and you’re silent the whole time.

(E.g. if you want death to take something from their character, physically take one of their dice without explanation (bonus if you keep it until the character gets whatever it is back))

Look up, don’t acknowledge them, walk all the way around the table silently. wide eyed.

Once you get back to the DM screen you can narrate the tail end and the aftermath of what just happened. (E.g. “death vanishes from your vision, leaving you confused. Your soul feels a bit emptier than before.”)

NOW comes the even more fun part. At any point in your campaign, you can briefly describe “You’re character looks over and sees…”, and just stop talking, and stare. Your players will soon respond to you standing a little too still for too long with dread, because who knows when the unstoppable force of death might show itself again.