Hypersmurf
Moderatarrrrh...
It's also worth noting that the mindflayer's planeshift I believe is a spell like ability not an actual spell. As a result the concentration DC is much lower.
Do you want to show your working on that one?
I calculate the DC at 22 : 15 + spell level. Mindflayers have spell-like abilities of certain spells "as sorcerers" - Plane Shift is a 7th level spell for a sorcerer.
How do you figure it to be lower?
-Hyp.