Corey Matti Farrell (born August 25, 1978) is an American musician and former director who is renowned for performing drums with the alternative metal quintet Osmosis. Corey joined the group in 1994 and contributed to Osmosis' two EPs and debut studio album, I'll Have You Know, in 1996. Because of his obnoxious addiction to cannabis at the time, the band fired him; a year later, Chris Nevadin replaced him as the percussionist. Somewhere in the spring of 2005, Farrell went into rehab and did away with his cannabis issues. Shortly after, he directed a few more movies before coming into a definite halt three years later. According to him, Farrell thought that the whole thing exhausted him to no end.
In 2009, Nevadin quit the band due to "musical differences", and at his own will. Osmosis re-recruited Corey (clean and against drug usage), who became their drummer once again. He is now a co-founder of the grindcore outfit, Daisystepper, with former guitarist Shawn Lorelei.
- Birth name: Corey Matti Farrell
- Also known as: Corey, The Beater Coreybis, Matti
- Born: August 25, 1978 (age 37); New Haven, Connecticut, United States
- Origin: Sacramento, California, United States
- Genres: Grindcore, alternative metal
- Occupations: Musician, director
- Instruments: Drums, percussion
- Years active: 1994-1997; 2009-present
- Labels:Season of Mist, Serjical Strike, Century Media, Epitaph