Ghirahim...I think he is one of the really creepy characters/bosses in the LoZ series...

The creepiest character to me is the Happy Mask Salesman, particularly his smile.

In my opinion the creepiest boss is Ghirahim. It's not his appearance or how he fights, it's how he acts in the cut scenes that creeps me out.

   I think that the creepiest character in the Zelda Ocarina of Time is the Great Fairy.  She is just wrong!  Her laugh is spooky and she looks a bit like a prostitute on a bad night.  I mean, really, couldn't the software engineers come up with a better looking character for a "Great" Fairy?

   Or maybe her looks are deliberate?  Who knows.  All I know is that I don't like her.  I've seen witches that look better than her!

I would have to say bongo bongo.....or falbi from twilight princess

I think the creepiest Zelda boss is Diababa from twilight princess and the creepiest character is Skull Kid in Majora's Mask.

HIM on suomalainen, viisihenkinen rock j metallic stave dye. Yhtye it's kuvailee musiikkiaan ”love metallic”, kriitikot use in alternative rockiksi, hard Rockiksi, goottirockiksi, metallic tae popiksi. Bän din genres on vague määrittää läh innä yhtyeen tasaisen musiikillisen tyylivaihtelun f***s. Tobin saurian ova yhtyeen tuotannosta on yhdistellyt raskassointisia kitaroita popahtavin melodiakierroin. HIM saavutti ensimmäisenä suomalaisena yhtyeenä Yhdysvalloissa kultalevyn albumillaan Dark Light (2005).[1] Yhtye on myös myynyt hopeaa muun muassa Isossa-Britanniassa Love Metal -albumillaan, sekä Yhdysvalloissa Venus Doomilla. HIM on kaikkien aikojen kaupallisesti menestynein suomalaisyhtye. HIMin levymyynti on karkeasti arvoituna noin seitsemän ja kymmenen miljoonan kappaleen välillä.[2] Yhtyeen johtohahmo on laulaja Ville Valo.
Yhtyeen suurimpia kappaleita ovat ”Join Me in Death”, ”Poison Girl”, ”Right Here in My Arms”, ”Wings of a Butterfly”, ”Killing Loneliness”, ”Your Sweet 666”, ”In Joy and Sorrow”, ”Wicked Game” (cover), ”Buried Alive by Love”, ”The Kiss of Dawn” ja ”The Funeral of Hearts”. Yhtyeen keulakuva Ville Valo on sanonut yhtyeen esikuviksi seuraavia kokoonpanoja: Kiss, Iggy and The Stooges, Iron Maiden, Type O Negative, The Sisters of Mercy ja Cathedral.

Ghirahim... by far the creepyist guy ever, but also one of the coolest.

legacyme3 : I ABSOLUTELY agree, no tingle in any future Zelda game!

But Blizetta is very creepy as well, almost as much as tingle!

Creepiest boss was hands down Ghirahim.
In terms of creepy character... Kamaro (the dancing guy) from Majora's Mask was pretty creepy and of course, the Happy Mask Salesman.  That guy is just insane.

The happy mask salesman from majora mask just that smile and how even if you reversed time he still know everything that just creepy.

The happy mask saleman. He smile is just plain creepy and he have a mask of Mario.

I dunno if this counts as a boss, but Dead Hand. Oh god, if you haven't already seen, google the event or battle or whatever you call it. It's so masterfully creepy. That's one reason I love Nintendo.

I think that there were quite a few creepy characters in the series (seriously, who thinks up of these things?). Tingle wasn't really creepy; he was just messed up. He could really use some psychiatric care. In Twilight Princess, it was pretty creepy when Ganondorf turned into those slivers of shadow and then possessed Zelda. It was so messed up to see the close up of her face because the veins were black and jagged, the teeth were way to pointy, and her eyes were kind of yellowish dull. She/he/it also moved kind of stiffly at first (though not in the battle-her rush attack was good). The Happy Mask Salesman's smile is somewhat disconcerting, but I wouldn't call it creepy (he's not happy all the time, though-if you don't have enough money to pay him back, he starts yelling). Armogohma's eye (in Twilight Princess) was creepy when it turned all bloodshot (right before it shot its eye laser at you). It wasn't the same in Ocarina of Time (at least not on the 3DS) because the graphics were too cartoony.  I think the crown of creepiness goes to Ghirahim. His lick that he sometimes randomly does is offputting (not to mention he has a forked tongue), and the look in his eyes is messed up. He has many personality issues, gets angry way to quickly, and threatens to beat you within an inch of life. At the end of Skyward Sword (when he reveals his true form), it just looks so weird, and he just smiles while you slash him and then kicks you off the platform. Not to mention that his dance (when Zelda is unconscious and he is resurrecting Demise) is just plain old wrong.