This is a newer version of the Villager Prision (Or Villager Drowner if you want to call it that).
Once you managed to put you unlucky villagers into the structure, you can either keep them there or kill them.
Version 1 only had drowning, but this version has multiple ways for your doomed villagers to die!
Try using them all, you never know which one's your favorite!
If you liked this, diamonds and favorites would be appreciated!