Season 2
Michael - Two-headed Michael
Dwight - Sith Lord
Phyllis- Cat
Pam - Black Cat
Creed - Vampire
Jim - 3 hole punch Jim
Angela - Cat
Oscar - Woman
Kevin - Mr. Incredible from The Incredibles
Stanley - None
Kelly - Dorothy from the Wizard of Oz
Ryan - None
Meredith- zombie
Toby - Pajamas
Devon - Hobo Clown
Season 5
Michael- unknown
Dwight- The Joker
Pam- Charlie Chaplin
Jim- A guy named "Dave"
Andy- Kitten from Cats
Oscar- Uncle Sam
Kevin- The Joker
Angela- Cat
Meredith- Cheerleader
Phyllis- Ragedy Ann
Kelly- Carrie Bradshaw (Sex in the City)
Ryan- Gordan Gecko
Stanley- Creature from the Black Lagoon
Creed- The Joker
Season 6
Michael - Dick in A Box / Suicide Victim
Dwight - Jigsaw (Saw)
Jim - Facebook
Kelly - Leeloo (Fifth Element)
Erin - Fiona (Shrek)
Angela - Black Widow spider
Creed - "Original" Vampire (Dracula)
Ryan- "Trendy" Vampire (Edward from Twilight)
Oscar - Sarah Palin
Kevin - police officer
Phyllis - witch
Stanley - torture vicitm
Pam - Rosemary (Rosemary's Baby)
Darryl - "Gangster" Pumpkin
Meredith - Hobo
Mose - Scarecrow
Season 7
Michael - Mcgruber from Saturday Night Live
Dwight - Scranton Strangler
Jim - Popeye
Pam - Olive Oyl
Andy - Bill Compton from TrueBlood
Meredith - Sookie Stackhouse from TrueBlood
Creed - Mummy
Kevin - Michael Moore
Stanley - Samurai Warrior
Gabe - Lady Gaga
Kelly - Snooki, then Katy Perry
Ryan- Justin Bieber
Oscar- 1970's disco guy, the "Rational Consumer"
Angela- penguin, sexy nurse
Erin- monster mask
Toby- hobo (same costume that Devon wore in season 2)
Darryl- vampire
Todd Packer - pregnant nun
Phyllis - nun --- or Supreme Court Justice
Season 8
Andy- Construction Worker
Jim- Chris Bosh
Kevin- Dwyane Wade
Darryl- LeBron James
Pam- kangaroo
Creed- Osama Bin Laden
Dwight- Kerrigan from Starcraft (later a jamacain zombie woman)
Meredith- Kate Middleton
Toby- Skeleton 1
Gabe- Skeleton 2
Kelly- Skeleton 3
Ryan- Jesse Pinkman from Breaking Bad
Oscar- Oscar Liar Weiner
Erin- Wendy from the fast food restaurant "Wendy's"
Angela- Kitten (same cat costume as in earlier seasons)
Phyllis- unknown, possibly a broadway performer
Stanley- Chef (from South Park lol)
Season 9
Andy - George Michael
Jim - No Costume
Pam - Doctor Cinderella
Dwight - A Pig
Phyllis- A cheerleader
Nellie - "Sexy" Toby
Stanley - Usain Bolt
Creed - Splattered with blood (implies he is not wearing a costume - says "it's Halloween. That is really, really good timing.")
Meredith - Black Widow
Clark - No Costume
Kevin - Charlie Brown
Angela - Nancy Reagan
Oscar- A Dinosaur (tells Senator Lipton he is the Electoral College)
Darryl - Unknown
Pete - No Costume
Erin - A Puppy