After two episodes wearing the same makeshift Svengoolie outfit seen in his appearances on Toon in with Me (2021), Sventoonie debuts a sleek new look in the third episode of this show (Specimen Container! (2022)), with a new yellow-trimmed costume and better-styled hair and makeup applications.
Sventoonie is the horror host alter ego of Toony the Tuna from MeTV's weekday morning cartoon anthology, Toon in with Me (2021), first appearing on 18 March 2021 with the special Svengoolie (1995)-styled horror-centric episode, Sventoonie (2021). Humorously referred to as an "unsanctioned spin-off", Sventoonie's look borrows heavily from Svengoolie, and on "Toon In with Me" his sidekick Billwyn (Bill the Cartoon Curator dressed in a chicken suit) is derivative of Svengoolie's prehistoric rubber chicken sidekick Kerwyn. With considerable overlap in the viewership and fandom of "Toon In with Me" and "Svengoolie", the crossover Sventoonie character became a fan favorite and would return periodically, in episodes such as Return of Sventoonie (2021), Attack of the 50 Ft. Sventoonie! (2022), and Sventoonie Is Out of This World (2022).
Because of the short, half-hour runtime of the show, featured horror movies are presented in condensed versions, accompanied by Sventoonie's running commentary.
Sventoonie hosts his solo spin-off series from Svengoolie's dungeon studio, while Sven sleeps in his coffin after wrapping his weekly show.
The main cast of the spin-off series includes Sventoonie ("Red Tuna of Terror") and brand-new characters Blob E. Blob ("Blob of the Macabre" - Sventoonie's blobfish sidekick and sound effects generator) and Trevor Ground ("Dead Video Store Guy" - an undead employee from a defunct 1980s video rental store), with special appearances by Svengoolie ("Award-Winning Horror Host") and Kerwyn ("Chicken Diddle" - Sven's prehistoric rubber chicken sidekick).