So, I'm not very familiar with End Crystals, but something strange happened. I was building an obsidian tower about as big as, say, a pretty tall tree. I placed an End Crystal on top, and I was kind of surprised that it worked. I was earlier, before I even made that, using command blocks to teleport myself to some islands I made. I had been making a Skywars world. Anyway, it kept saying two entities were teleported, but really it was just me. Once I built the whole thing, I turned around to work on another command block. I also spawned a group of about 10 villagers to play, and when a I tried using the block, I turned, facing the islands, and I saw the End Crystal huddled between a group of villagers! I destroyed the End Crystal which blew up and killed all the villagers.