Someone on the OOTS forums pointed out that this beholder has 8, not 10, eye stalks. The Eye Tyrant (aka NotABeholder) mini from Monster for Every Season has 10 eye stalks, so oots style beholders have been drawn both ways. If that means this is the same beholder… I don’t know.
The beholder in strip 32 also has 8 stalks.
It is presumed that Sunny is Invisible Orange Voice from the final strip of the last book.
Speculation about the 1-page Important Ally has considered the possibility that Orange Voice is said ally. Many people think it would be disappointing, even a bit of a cheat, if they turn out to be the same.
In any event, if Sunny is the Page 32 Beholder, that would be two prior appearances, ruling her out as the 1-page Ally.
But Sunny didn’t “appear” in the orange voice strip. Sunny was invisible.
Yes, that word game has been used in the discussion.
For what it’s worth, the “Number of Character Appearances” thread on the GiantITP forums counts a word bubble, even from an invisible or offscreen character, as an “appearance”. And Burlew has made reference to that thread before, so he at least knows of its existence.
That not-stone creature is presumably Mimi. What is Mimi, some kind of shapeshifter or illusion?
Sunny the Friendly Beholder was a great reveal. I trust we will eventually learn its backstory.
Exactly and that’s why Beholders are awesome. 
I suppose Rich could resolve his legal problems by calling it a RAM or Range Attack Monster. Although in reality I suspect he simply secured permission.
I would assume Mimi is a Mimic, who took the form of a pile of rubble rather than the more typical treasure chest.
Eye Tyrant is the generally accepted name I believe, he used it in his Monsters for Every Season thread.
Other options could include Ocular Horror? Gaze Beast? Abberant Looker?
I was assuming that Mimi was an earth elemental, who was hanging out within the wall and only stepped out into the doorway (and was just big enough that her broad back was indistinguishable from a door). But you’re right, there is a pile of “rubble” there that coalesced into the form we see in panel 6, and the name “Mimi” certainly does seem suggestive of “Mimic”.
Either way, it’s certainly “no magic, no mechanics”, like Haley said.
Aside: Back in my teen years, I came up with stats for a Cherubim, as depicted in Madelyn L’Engle’s A Wind in the Door. And realized in the process that what I was actually making was a good-aligned variant on the Beholder. Or more likely vice-versa, with beholders existing as a mockery of cherubims, much like (according to Tolkien) trolls were mockeries of ents, or orcs of elves.
Right. In D&D, a mimic is a shapeshifting ambush predator, which takes the form of inanimate objects to lure in its prey. The iconic/cliche form is a treasure chest, which eats the hapless adventurer that tries to loot it, but a mimic can take on virtually any form.
In this case, Mimi the mimic apparently took on the form of stone(s), to lay undetected near the entrance, then took on the form of a stone plug that fills the door. It would look, feel, even smell like stone, so it would be virtually undetectable, even to a dwarf’s “stonecunning” ability. But it’s not actually stone, so it’s not affected by spells like stoneshape or passwall.
It’s too bad Haley didn’t think to check of [Su]pernatural abilities or [Ex]traordinary powers.
I remembered a fan theory that suggested mimics could grow into doppelgangers (humanoid shapeshifters) and then into this massive monster that mimics whole buildings or Dungeons to eat adventures - but instead I found this cool reddit post about mimics, including a cool theory in the comments about how they reproduce that I’m totally stealing.
As soon as I saw that strip title, I knew what to expect, and wondered why it hadn’t occurred to me sooner.
Poor Belkar.
Oh, and one other very important point in this strip:
Serini refers to Haley as the leader. Which means that she does not, in fact, know the party nearly as well as she knows the paladins.
Oh! I just got it now. I’d been wondering about that.
Or her awareness of them comes from when Roy was dead.
I was browsing the GITP forum yesterday and several people had anticipated this move. More impressively, one guy had literally previously predicted an amiable beholder as the orange voice. Which brings us to Burlew’s rather deliberate, tongue-in-cheek avoidance of the creature’s name.
A rapid-fire crossbow?
I’ve seen numerous “repeating crossbows” in D&D over the years (homebrew or otherwise). Not realistic but, yeah, D&D right?