I really like that idea. Worms can be super creepy and making them monsters could be horrifying. I hope you follow the idea and make epic worm monsters. 

That is cool. Why not do both? The mayor has a blood worm that will take over their body at the end of the festival. You have time to stop it, but not too much.

Normal human by day. Giant blood sucking worm by night. A game where you have to figure out who is acting a little too wormy before nightfall sounds as funny as it does scary.

Now that you mention it blood worm moon does sound like the tile of a Junji Ito story. I like the way you are thinking.

I would <3

I never played much Terraria, but I do know the boss. I always thought it was as creepy as it was cool.

XP. Thanks for reminding me about that. I truly hope you make something based off it.

That is a really fun idea. I could see myself playing as an evil worm druid, but I can also see myself fighting evil worm druids (possibly as an evil worm druid). I know you didn't use the word evil. Blood worm moon just sounds evil.