Karen Leigh Prell is a puppeteer and animator. Born in Florida, she first worked with Jim Henson in 1979 in small roles on Sesame Street. She subsequently worked on the final season of The Muppet Show, assisting and playing various bit parts (such as the title character in "Rockin' Robin.") She also performed Deena and others on Sesame Street in the early '80s, but made her greatest contribution performing Red Fraggle on Fraggle Rock.
Prell also performed on the Creature Shop films Dreamchild and Labyrinth. During the latter film, she first became romantically involved with future husband Mike Quinn, as they made each other's goblins flirt during lulls in shooting.
In 1997, Prell transitioned into computer animation, working on several Pixar projects, including the shorts Geri's Game and For the Birds and features A Bug's Life and Toy Story 2. Recent animation credits have included some of the CGI animation in Disney's Enchanted, work for Tippett Studio on The League of Extraordinary Gentlemen, Son of the Mask, animating the award-winning video game Portal 2, and Frank Oz's The Stepford Wives.
Demonstrating that her affection for the Muppets has not waned, however, Prell attended MuppetFest in 2001, resplendent in a homemade Red Fraggle cap, and also participated in the Fraggle Rock: Complete First Season bonus features. In 2005, she reprised her role of Red Fraggle, in voice over, as host of "Fraggle Challenge," a bonus feature on the Doin' Things That Doozers Do and Down in Fraggle Rock DVD'
- Sesame Street: Deena
- Fraggle Rock: Fluffinella, Red Fraggle, Baby Tree Creature, The Beast, Gorg's Killer Souffle (body), Judge Gavel Doozer, Marly Fraggle, Modem Doozer, Sprocket (assistant), Wingnut Doozer, Balsam the Minstrel (occasionally)
- The Fantastic Miss Piggy Show
- The Muppets Take Manhattan: Yolanda the Rat
- Dreamchild: Dormouse (puppeteer)
- Labyrinth: Firey 2 (lead puppeteer), The Junk Lady (puppeteer), The Worm (puppeteer), Helping Hands, Goblins (puppetry only)
- The Tale of the Bunny Picnic: Babble, Baby Bunny, Great-great-great-great Grandmother
- A Muppet Family Christmas: Maureen the Mink
- The Ghost of Faffner Hall: Mimi
- Mother Goose Stories: Gosling #1
- The Muppet Christmas Carol: The Ghost of Christmas Past (puppetry only), Daughter Mouse
- The Animal Show: Alexis the Giraffe, Bernice the Warthog, Hetty the Hedgehog, Kasey the Kangaroo, Ollie the Tapir (first season only), Tizzy (first season only), Leah the Fruit Bat, Lydia the Ostrich, Arlene the Aardvark, Hillary the Owl, Charlotte the Penguin, Rhonda the Raccoon, Kasey the Kangaroo, Mother Kangaroo (voiceover), Baby Warthog (voiceover), Mother Bear (voiceover), Hetty the Hedgehog, Mother Roadrunner (voiceover), Blanche the Manatee
- Muppet Treasure Island (Uncredited) 
- Sesame Street 4-D Movie Magic
- Late Night Buffet with Augie and Del: Spank
- [http://muppet.wikia.com/wiki/The_Muppets_(2011) The Muppets