Well that is odd. I have caught a unknown and I went to the maniac cave..

Have 10 Unown and the cave will expand have 26 Unown and he will tunnel into the Solaceon Ruins so you can catch the other 2 all the Unown have to be A-Z.

You have to catch all the letters of the unown then the maniac will open a cavern to the unown "exlimation point" and "Question mark" so you have to catch all the different letters to make him move further into the cave. Hope this helps!

You need to catch all 6 Unown. It's honestly not worth it, though, because once you do catch all 26 Unown, he'll dig up to a new ruin where you can catch Unowns ! And ?. And that's it...

That guy is digging a cave. When you catch every unknown (26 of them A-Z), he will be finished digging and the cave will be extended. In the very last room, you can catch the unown ! And ?.

Lol, same thing happened to me, you have to catch ALL the unknown then talk to him

You must have all unknown data on your pokedex then talk to him

Just so you know, there are 28 different forms of unown. One for each letter of the alphabet which accounts for 26 forms and the remaining two have puncutation mark forms namely ! And ? I'm not totally sure what happens if you manage to have all 28 forms and talk to him but I do know that the probability of finding geodude in his cave decreases with the more unown you have and the probability of finding hippopotas in his cave increases. With that in mind, it's hardly worth it catching 28 of the same thing basically.

You need to catch all the unkown first then talk to him

Okay lovestoplaygames, even though I have Pokemon Pearl Version, I can answer your guestion. The ruin maniac, he doesn't want one Unown, he wants 26 different ones. He wants letters A-Z. You don't get anything for getting them, but when you have one of each letter, his cave will be huge! In the back will be a passageway. Go through, and you can catch the ? And ! Unown. I'm going to give you a bonus. I'll decipher the cave words for ya! These are directions to rare items. Go into the rooms in this order: top right, lower left, top right, top left, top left and lower left. In the final room, the wall says: "Friendship, all lives touch other lives to create something anew and alive." If you have any other questions, ask me! I'm the guy who can really help! (P.S: He doesn't keep your Unown, you keep them, but all they know is Hidden Power. ALL OF THEM!)

He does not take your Unown. You need 10 Unown for His cave to go deeper. Once you catch the 26 letter Unown, he will punch through a wall that will contain a chamber filled with Unown ? And !.

Well I know this, I catched all the Unknown Pokemon, and you can show the unknowns to a kid who will give you seals for each of the unknowns you show him, and as a bonus if you are carreing a unknown in maniacs cave you will have a chance getting a rare ground Pokemon called hippopotas. And thats about it