Who can beat Mephisto in his hell?

ION, Parallax, Lucifer, Michael, Dream...

superman 1 million AKA kal kent

in his hell he was beat by thanos

amazo, 

Belasco and Magik

Thanos, Darkseid, Silver Surfer, Lady Death and Spawn to name a few.

"@Hellos:  he stalemated galactus in hell so maybe not "

" Belasco and Magik "

" kimbo slice "

Spectre. 

"@Hellos:  in the acctual batte they appeared very even although galactus was hungry and apparently not bothered by mephistos attacks   "

he has been 'beaten' in his hell on a few occasions. Silver Surfer/ Dr Strange/ Thor.. and what not. 

However if you mean 'beaten' as in Destroyed/ Anihilated.  Then.... thats pretty hard.  
 
I dont like the " i live in the hearts of my worshippers " crap... so im going to say Galactus... or maybe a Celestial.

odin.

the original powers of the universe (Eternity, Infinity, Death, Oblivion, Phoenix and Living Tribunal)
Galactus almost devoured his hell.. 
Chthon would make Mephisto feel like a fairy before the demon among demons.. 
Vishanti 
 
and many more..

Hyperstorm

Mephisto

Divine Spawn, Jackie Estecado, Sara Pezzini, Danielle Baptist with the Angelus, Savior Cable, X man, Kenneth Irons, Apocalypse, Franklin Richards, Dr Manhattan, Dante, Jedah, Morrigan, Onslaught, Ian Nottingham, Lucifer, Hope from Topcow, Jesus Christ, The Wanderer, The Elder Gods, Juggernaut, Odin.

Bugs Bunny

divine spawn?

Galactus already did it, didn't he? Ghost Rider, Thanos, a good bit, but not quite too many.

pikachu

"whose book is it?" reasoning might be in order.

Pit from Kid Icarus: He went though the underworld and fought his way to get though angel land, which was infested with evil creatures to get to medusa. Her defeated her   and done it   while start off bow that could shoot far and not having the ability to fly.

Optimus Prime if his evil gone too far he can use the all spark/power pack/matrix

Kratos: he been though the underworld twice    

" Galactus already did it, didn't he?

COIE Anti-Monitor

and

Chuck Norris!!!!!!!!!!!!!

Galactus, Beyonder, TOAA(celestial), TOAA(the god of marvel), Spawn, Thanos, Ghost Rider, Ares(dc), Blackheart, Dormammu, Unicron, Primus, Spectre, Living Tribunal, Darkseid, The Presence, Man Of Miracles, Malebogia, Michael Demiurgos, Lucifer Morinigstar, Franklin Richards, Doctor Doom, Dark Phoenix, Eternity, Solaris, Super Sonic(archie), Super Shadow(archie), Super Silver(archie), Doctor Manhattan, Saint Of Killers, and Bugs Bunny,

Adam Warlock already did :)

SOK easy.

Lucifer Morningstar.

@JackKnight said:

COIE Anti-Monitor

and

Chuck Norris!!!!!!!!!!!!!

Pikachu is the next Chuck Norris!

dormammu

@GodDamnIronMan: F**k Pikachu!!!!!! Clint Eastwood for the win!!!!!!!

Bugs Bunny and Squirrel Girl fear the day when they meet Clint Eastwood! Not even Bugs Bunny's overrated toonforce carn't defend him against Clint's 44 Magnum the most powerful handgun in the world and Squirrel Girl's off panel ability is useless against Clint's epic quickdrawing power!!!!!!!

Dormammu with ease!

Shuma-Gorath

Dormammu (Already been done in the comics)

Galactus (Already been done in the comics)

Anti-Monitor

The Mask

Mr. Mxyplktz

Spectre

The Hunger

Mordru