Bugbear

A humanoid hostile mob that looks like a hairy mob, and appears at midnight when certain conditions are met.
This mob searches for villagers, and when they find them, they attack to kill them.
When it finds a player, it prioritizes the player over the villagers and attacks to kill that player.
However, this mob has special conditions like the phantom, and it will not appear unless the conditions are cleared.
The conditions are that the number of villagers is overwhelmingly large, and that the player stays in the village for a long time (including the village created by the player).
If this condition is met, this mob will appear.
However, it will not spawn in villages with no players or if players have only stayed for a short time.
The biggest feature of this mob is that it scares the villagers with a terrifying voice.
For the villagers, it's more scary than zombies or Illagers.
Of course, the Iron Golem shouldn't be left alone, and as soon as it's found, it fights the mob to protect it from the villagers.
It's not an undet, so it won't burn, but it will disappear at dawn.
If you have any other good ideas, please let us know in the comments.
Thank you for sharing my idea.