I griefed my sister's creative world by making a really big lag zone. I spawned a bunch of NPCs using dispensers and eggs. Our PC is really bad so I couldn't go close enough to kill them in any way, lava, diamond sword, or TNT. The lag zone is so bad that we couldn't use a TNT cannon.
In addition, our dad doesn't allow us to download mods so don't mention downloading single player commands and do /killall
.
Please note that they are NPC villagers that are causing a lag zone.