The bug
You can respawn the ender dragon using only two end crystals in survival mode. Typically you are required to have four end crystals to respawn the ender dragon so I believe this to be a bug.
How to reproduce
Place Water so that it flows into and replace all (or most) of the exit portal blocks. You can use either downward facing dispensers or water placed on the edge of the exit portal/bedrock pillar to do this.
Place end crystals on the bedrock under the portal
Observe the ender dragon respawn sequence
This is due to the large hitbox of the ender crystals overlapping the detection boxes end crystals positioned on the portal edge.
Video of how to reproduce can be seen here: https://www.youtube.com/watch?v=qOdaxnEhWbI
Video of how to reproduce WITHOUT using water buckets, but with mushrooms, here: https://www.reddit.com/r/Minecraft/comments/kgusao/how_to_summon_enderdragon_with_only_two/
The picture shows how to position the end crystals to get this to occur.
Linked issues
is duplicated by 1
Attachments
Comments 15
If MC-11944 is fixed, then this would be impossible to reproduce without finding some other method to break portal blocks
It would be impossible in survival, but creative players can break any blocks, so it won't be an issue.
Still an issue in 1.12.2. Also, this can be used to remove a End Portal completely from the world in a normal survival world since each time this is done, the portal itself moves downwards by one block.
Still an issue even for survival players in 18w06a however the end portal can no longer be moved downwards by using two Ender Crystals so the issue is less severe.
Can confirm in 1.17.1. When you interrupt the spawn sequence by breaking one of the crystals, it generates a few end portal blocks in one of the corners of the bedrock fountain, instead of the complete portal.
Can confirm.