How *Fun* Are Beholder Fights?

[Pixel_Kitsune]

I would STRONGLY advise getting rid of the Random eye beams, either entirely or at least for the main action 3 beams. I tend to run them with the following (I don't detail the beams themselves since that's WotC property):

Eye Ray: The Beholder fires 3 eye beams of its choice from below.

Charm Ray: Can only have one target charmed at a time.

Paralyze Ray, Fear Ray, Slow Ray, Enervating Ray, Sleep Ray: Business as Usual

Petrification Ray, Disintegration Ray, Death Ray: Each can only be used once per Round (Per round, not turn).

Legendary Action: Use a Ray of the Beholder's choice (Keeping in mind, above, so if you used Death ray as a normal attack you can't Legendary Act it too)

I also would consider bumping HP up to 250 depending on the party.

Now a few corrections or comments from earlier posts.

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.

Monster Manuel mentions the beams that get saves each round. Charm isn't one of them, It specifies the target is charmed for 1 hour or until the Behold Damages them. So charming a target can quickly give the Beholder an Ally and force the party to take action to trick the Charmed target through the Anti Magic Eye or hit them with Calm Emotions or Dispel.

I've run 2 Behold Encounters in 5e (More before, but not important here). The first was a group of level 8's and was fun on both sides, I was running the adventure from Candlekeep with the one trapped in a painting. The other was level 2's, the group stole Sylgar... Because of course they did.