Quote Originally Posted by Pixel_Kitsune View Post
Telok mentions them being boring from 10th level on. They're only a CR 13 so that's to be expected. You need to ramp them up for Tier 3 and 4 encounters.
It's not that you need to "ramp up" the beholder. It's that shutting off the mundane's gear & buffs in T3+ is a bitch that makes them stop, recalculate stuff, wastes time, and introduces mistakes. Combined with it's abilities being either "move a bit and ignore it" or "guess what saves you're making this round" means that everything interesting about it leans on the GM setting up an interesting location. But if you've got a good location you can make pretty much any fight interesting.

Even basic zombies can be an interesting fun fight at high levels with the right scenery & set up. The corallary being that no matter how fancy the monster, if you fight it in an empty box it's probably going to be pretty dull. Ultimately beholders just aren't very interesting in a mechanical sense any more, an antimagic cone and random saves attached to a pile of hp aren't inherently interesting or fun.