phyllusSeason 2
Michael - 2 headed Michael
Dwight - Sith Lord
Phyllis- Cat
Pam - Black Cat
Creed - Vampire
Jim - 3 holed punch Jim
Angela - Cat
Oscar - woman
Kevin - super hero
Stanley - unknown
Kelly - Dorothy from the Wizard of Oz
Ryan - "Jessie Pinkman"
Meredith- zombie
Toby - unknown
Devon - a homeless man
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 from Sex in the City
Ryan- Gordan Gecko
Stanley- Creature from the Black Lagoon
Creed- The Joker
Season 6
Michael-Dick in the box
Dwight-Jigsaw
Jim-Facebook
Kelly-Leeloo from fifth element
Erin-Fiona (Shrek)
Angela- Black Widow spider
Creed- "original" vampire
Ryan- "trendy" Vampire
Oscar - Sarah Palin
Kevin - police officer
Phyllus - witch
Stanley - torture vicitm
Pam - ???
Season 7
Michael - Mcgruber from Saturday Night Live
Dwight - Scranton Strangler
Jim - Popeye
Pam - Olive Oil
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
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
Season 8
Andy- Construction Worker
Jim- Chris Bosh
Kevin- Dwayne 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 "Wendys"
Angela- Kitten (same cat costume as in earlier seasons)
Phyllis- unknown, possibly a broadway performer
Stanley- Chef
Season 9
Andy - George Michael
Jim - No Costume
Pam - Docter 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