Thanks @Greboth for that explanation. @Sennex, he wanted to just respawn it in Creative as he killed it once and didn't know how to respawn to kill it again.
I'll need to look into these End Cities though, they sound like real fun. Difficulty is my son started on survival, enjoyed it, but as soon as he seen youtube videos to play creative he just wanted to do that and not wait for things. Shame really, takes the fun away from earning stuff like how Greboth explained it.
until