Minecraft wiki entry for Defeating_the_ender_dragon, associated text: Keep exploring the stronghold's hallways until you find the end portal room. Collect any chest loot that you find. As soon as you see the portal room, run in as quick as you can, as an active silverfish spawner sits in the broken staircase that leads up to the portal. Kill all the silverfish in the room and destroy the spawner. You can also place a stone brick stair in the empty space to complete the staircase, which eases the walk up to the portal. It is also recommended that you quickly turn the lava into obsidian because silverfish could emerge from the blocks beside the lava basin and it could cause you to be engulfed in lava.