A boy is tired of failing geometry, so he summons a demon.
| Directing | Guillermo del Toro | Director |
| Sound | Christopher Drake | Music |
| Writing | Guillermo del Toro | Writer |
| Writing | Fredric Brown | Short Story |
| Production | Javier Soto | Associate Producer |
| Production | Guillermo del Toro | Producer |
| Production | Adolfo Camacho | Executive Producer |
| Editing | Sigfrido Barjau | Editor |
| Editing | Peter Devaney Flanagan | Editor |
| Art | Daniel Varela | Art Direction |
| Sound | Alberto Castaño | Sound Re-Recording Mixer |
| Sound | Scott Martin Gershin | Sound Designer |