This hypetrain feels like playtbc . <| sep |> Your problem from a balance point of view in this case is the worm that walks template . A DR of 15 is pretty damn scary paired with the no discernible anatomy and high fast healing features . Unless your group is packing a lot of AoE attacks , which this thing is weak to , expect this fight to be hard to win bordering on impossible . Judging by the group composition , AoE seems thin . If you just throw this thing at them , chances are good they will get stomped . But especially because of this , I would absolutely NOT give them a deus ex machina to win the straight fight . Even with some sort of cost attached , doing so would cheapen the whole experience . Design the adventure in a way that allows them to learnsee what this guy is and make finding a way to beat him the main plot . Make them earn their win by finding out they need AoE and acquiring ways to have it , be it thru magic items , barrels upon barrels of alchemist fire or whatever else may be available . Note also that this guy is prime material for a recurring antagonist . You can always say that a few of the worms burrowed away underground or whatever and have him show up later , wanting vengeance . Killing this thing for real should be its own arc and should involve even more prep .