Kill people without /kill! by ximpulsiifsushii

I didn't use the generator to make this command, how did I know about this? Well, there is a hack to make Killer Potions and I thought:'If killer potions exists, it would be possible to make one in vanilla minecraft? I just used some simple thoughts and used negative instant health why? You don't take instant damage in gamemode 1 but I could use instant health in gamemode 1 so then i got the idea to do that and it worked, but how do u counter the effect? do /god. BUT! you need a plugin for it, and you need to be a staff member (On most servers except single worlds because it's your own world) but how to troll them again? /god (player). It will put the player out of /god. if he had it on.