wia

That still doesn't address vampiric touches life restoration RAI. Heck even RAW the spell says damage to others.

This is still a no go lol.

Having DMed too much. Nope.

This is easily a rule as intended type of thing. If you hit someone else. Sure fine, this is actually awesome and very creative and totally in the spirit of the game.

If you're just trying to break the game. Nope. RPGs aren't about trying to pull apart the systems in place for a group of friends to have fun. Not at our table anyway.

Even the damage dealt thing is silly. Is argue you cant deal damage to something that is fully damaged.

Cynical take: To kill us. Dark forest style. Send out automated drones and kill off all other life that could pose a threat.

Other thoughts: If aliens showed up it we wouldn't detect them in atmo, not as a quick fly by. We'd detect something huge like engines or something going real fast way out in space. Like on the edge of the system. If they were in our atmosphere they would make themselves known one way or another at that point.