Knight Otu said:
#337.
As for being under-CR'd, my first version added the victim's Constitution bonus to the number of rounds that the dragon needed to extract the brain. We decided to turn it into the flat five rounds for ease of use, and more importantly, to avoid having the dragon nibble at high-Constitution fighters for hours (Yes, the mind blast is a bit stronger than that of a mind flayer, which was a reason not to go with instant extraction, along with the huge grapple bonus a dragon will have). Would that have helped?
Nibbling brains? Nah, it didn't get close enough to do that. The danger of it is the wide area of the mind blast coupled with the duration (and the DC).
I threw the Great Wyrm version (CR 25) against my party of 12 18th level PCs (adjusted APL of 20, but they were extremely optimized and kitted out a bit above wealth by level guidelines). Technically, I expected them to avoid the fight, but it wasn't beyond the CR they'd defeated before; this same group of players took down the aforementioned (CR 21) Deathjack at 12th level and an Iron Kingdoms dragon of about CR 25 at 14th level, albeit in a previous campaign - but they'd killed a CR 21 demon at 12th level in this one, so I wasn't too worried.
Let's just say they didn't avoid the fight.
I knew there was a problem when the dragon mind blasted the party... and they all needed at least 18s to make their saves. Well, not to worry, I thought; they may get stunned, but what's the worst that could happen? Trouble was, the dragon could use its stun an average of every 2.5 rounds, with a duration of
13.5 rounds - meaning once it stun-locked the PCs, it never had to let any of them get un-stunned, and it could re-use its mind blast often enough to ensure they all got stunned.
Part of the problem was that the PCs had had an extremely powerful save buffer character among their number for the previous 10 or so sessions, who had been killed the session before. So I was expecting their Will saves to be about 10 higher than they were. I ended up stopping the session and we agreed not to use the blast, and it was an interesting fight from then on.
It's just one of those creatures you can't really use against a lower-level party, no matter how numerous or well built; if I'd used, say, the very old version, it still would have been an impressive and deadly monster, but more in line with what the PCs could handle.