The Hallowe'en Wallpapers is a special edition of Sonic the Comic Online released Hallowe'en 2010. Not strictly an edition of the comic, the site simply displays a selection of wallpapers where regular STC characters have dressed up in the style of another SEGA franchise. The project was organised by Calisto and almost all of the posters were coloured by her.
A couple of days after the initial publication, the site was changed to show all of the Back Issues, as well as making Issue 224 the "Featured Issue" of the moment. The wallpapers are relegated to a link between the two major sections. It has now permanently been moved to a position between links for Issue 252 and Issue 253.
The following is a list of characters featured, with their inspiration in parenthesis.
- Amy Rose (Ulala, Space Channel 5) - Shay and Calisto
- Big the Cat and Buddy (Decap Attack) - Nam, Shay, Calisto and Retro
- Blaze the Cat (NiGHTS) - Calisto
- Ebony (KapuKapu, ChuChu Rocket) - Shay and Calisto
- Knuckles the Echidna (Samba di Amigo) - Shay and Calisto
- Nack the Weasel (Gilius-Thunderhead, Golden Axe) - DSC and Shay
- Doctor Robotnik and Tails Doll (Sonic the Hedgehog and Tails) - Jin and Calisto
- Shadow the Hedgehog (Virtua Cop) - Stiv
- Sonic the Hedgehog (Ristar) - Stiv
- Tails (Billy Hatcher) - Marcus and Calisto
- Tekno the Canary and Shortfuse the Cybernik (Eileen, Virtua Fighter and Vectorman respectively) - Calisto and Retro
- Tikal the Echidna (Fina, Skies of Arcadia) - Smithy, Shay and Calisto
- Vector the Crocodile (Beat, Jet Set Radio) - Shay and Calisto
Many of the wallpapers are still missing as of March 2011, five months since the feature first appeared. Several of the characters present in the group shot are supposed to have their own posters, yet have not yet been added.