Filed from 2 published puzzles

WHATINTARNATION

Set to 2 different clues across 2 published puzzles, most often "Huh?!" — The New York Times, Thursday, 30 August 2007.

15 letters

Every clue on record, most used first

"Huh?!"once
The New York Times — Thursday, 30 August 2007
Start of a perplexed person's questiononce
The New York Times — Friday, 21 March 2003

Other answers to these clues

COMEAGAIN9 letters
GEE3 letters
IDONTGETIT10 letters
ITMAKESNOSENSETOME18 letters
SAYWHAT7 letters
WHA3 letters
WHAT4 letters
WHATTHE7 letters
YOUREBREAKINGUP15 letters