u/Bluhr_the_dwarve

So this is probably a year or so away but I want to build up to it and I've painted myself into a corner a little. On going homebrew campaign 3ish years in. Currently level 7 planning to have them at level 10 for the final confrontation. The beg is megaroth as primordial/cosmic old one trapped in limbo, a gargantuan maw in space, all teeth blood, flesh, bone and general bad vibes that wants to eat the multiverse literally, my issue is I have no idea how to do it, my worry is having a stationary blob of HP at one end of the table and my players at the other, I've been playing and running games for nearly ten years but I can't decide how to end it. Current idea is they eventually get to limbo through a portal and there it is. I'm thinking some sort of staged boss fight, ala bg3 which I recently completed and think it is perhaps the way to go. But again I'm at a little bit of a loss thought about responding a sibrex or a malleable, from a mechanics point of view, corruption and fleshyness is the name of the game suggestions welcome