End portal

A portal with eye-like objects in it, which was surrounded by a luminescent golden material, was in a fortress which retreated into upon being seen by the Twelfth Doctor. Upon chasing him inside, the Doctor fell into the portal and landed in The End, along with the Ninth and Eleventh Doctors. (NOTVALID: Doctor Who Comes to MINECRAFT!)

Behind the scenes
Although the portal went unnamed in WC: Doctor Who Comes to MINECRAFT!, it was known in Minecraft as an End portal.