: His parents and neighbors have vanished, and his friends Gwen and Kevin act out of character, demanding he hand over the Ultimatrix .
The episode begins with Ben Tennyson seemingly waking up in a deserted version of Bellwood . He is immediately attacked by a , a parasitic creature that latches onto its victim's face to induce a coma-like sleep while feeding on their stress hormones .
As the episode progresses, Ben finds himself in a surreal nightmare world where:
: Ben eventually realizes he is in a dream and gains control over the environment. He deduces that the nightmare is actually a projection of Albedo's fears , not his own . In reality, Albedo had attempted to infect Ben with the Dream Eater but accidentally tripped on a smoothie, causing the parasite to latch onto his own face .
This episode is noted as a "bottle episode," featuring only the primary voice cast and using existing character models . Voice Actor Ben Tennyson, Albedo Ashley Johnson Gwen Tennyson Greg Cipes Kevin Levin Dee Bradley Baker Various Aliens (Swampfire, Four Arms, Big Chill, NRG, etc.) Production Details Network : Cartoon Network . Director : Dan Riba . Writer : Don McGregor (credited alongside Man of Action) .
: It is widely considered one of the "darkest" episodes of the franchise due to its psychological horror elements and the tragic nature of Albedo's defeat . Ben & Albedo's Nightmare World ft. O.R.Ash