Minecraft wiki entry for Player_versus_Player, associated text: In some cases, If they shoot at you or are rushing you without jumping, dig down, and place obsidian around you. Then get ready to crystal the top. If they dig down and try to mine through the obsidian or you're about to run out of end crystals, mine further down and block off the top. Since obsidian takes so long to mine, this strategy would likely last you long enough that the combat tag would expire and you'll be able to /home, which on most servers, takes idling for 5-10 seconds. Note while this is extremely effective in open battlefields, this isn't as effective in enemy bases, even if the floor is made of obsidian, as oftentimes, it'll be a flat floor which means you'll take just as much damage as your enemies.