Not gonna lie, I'm partial to Patchwerk, but the Four Horsemen just feels epic. So that'd have to be my favorite.
Thaddius has always been, and will always be, my favourite boss from Naxx.
Got to be Four Horsemen. Why?DAMNATION DAMNATION DAMNATION DAMNATION.
Grand Widow Faerlina on heroic did it for me, gotta love my handlock deck! Oh, wait...
Four Horsemen in WoW and I can't even beat the first one (Anub'somethingorother) in Hearthstone so no preference
NOOOOOOO! Kel'thuzad of course, but um, guys, poor mr. bigglesworth....My kitty D: You jerks!
Grand master Faerlena gave me a challenge I've not seen in a long time.
Anub-arak,
Definitely Heigen. Watching so many Fail to Safety Dance was a blast.
Patchwerk, he is so fluffy! (in a strange way)
Heroic maexxna :D I can't beat it but it's funny
Kel'Thuzad for sure. Have always love this character since the good old Warcraft days.
The Four Horsemen.
I've always enjoyed the four horsemen. Super interesting fight setup.
Thaddius and his screams.
Mexna
Grand Widow Faerlina, really tough boss on heroic, still can't win a match against her.
Heigan, FTW! I've died so many times because I was running on a potato PC and I can't dance
Currently Maexxna, gave me a bit of a challenge! :)
Frogger boss, close second it Heigan for the Safety Dance