Hello tabletop community,
I am designing my first ever boss fight, meant to really challenge my players. I don't want to kill any of them off since we're all new and it feels weird to lose a character, but I also want it to feel threatening. I could use some advice about how to execute this situation:
Boss is a big mimic disguised as a blood fountain with 6 long tentacle arms, each of which will be it's own figure on the board that can be up to 3 tiles from the 3x3 mimic figure.
Four of the tentacles have weapons that can deal 2d6 damage and have 30hp AC11 (roughly making it in line with a Brown Bear for threat and HP). They can grapple (squeeze the target) instead for 1d8 damage per turn, escapable on DC13 strength.
Two of the tentacles have shield-like hard points that defend neighboring enemies by giving disadvantage on attack rolls against them. AC14 HP30. I couldn't find anything to base these on for an encounter designer app.
Main body has low movement (10ft), and has 200hp AC19, and loses 20hp per tentacle lost. It has a bite attack +6 to hit 2d8. It also floods blood through sections of the room, forcing player movement and dealing 2d8 poison damage. I based it on a Roper for difficulty and attacks.
I think this combination creature would provide a very interesting and movement focused fight, but I'm very new to DM'ing and I'm afraid of accidentally killing the players.
My questions are: (1) How do I avoid accidentally killing everyone? (2) Is this fight too hard for a newbie group of 5 new players? (3) Any other cool ideas I didn't think of?