There are two games in the series. The first takes place in a creepy wasteland, and the second takes place in an underground cavern with acid pools. The was a planned third game with even a demo released, but it was cancelled and it is unknown if TheBlox will ever go back to it.
The Tails' Nightmare series contains examples of:
- Attack of the 50-Foot Whatever: In the second game, all difficulties above easy have the Tails Doll go into the background and enlarge himself, completely dwarfing Tails, as his final phase.
- Big Bad: In all three games, the Tails Doll is the one who traps Tails in the nightmare.
- Big Damn Heroes: The boss fight against Sonic.Exe ends with him surprising Tails with a lightning strike. Just as he's about to finish him off, a clone of Tails suddenly appears and knocks Exe into the lava.
- Boss Battle: One in each game, both against the Tails Doll. The demo for the third game also features a boss fight against Sonic.Exe.
- Bullfight Boss: One of Tails Doll's forms in the second game needs to be tricked into flying into spikes to hurt him.
- "Get Back Here!" Boss: Tails Doll's final form in the first game and first form in the sequel constantly teleports away from you, forcing you to hit him when he appears.
- Indy Escape: The fourth area in the second game features a fleshy boulder that chases you.
- Jump Scare: In the first game, after you beat Tails Doll, you run over to the right, and he suddenly catches you.
- Or Was It a Dream?:
- Tails wakes up from his nightmare only to have the Tails Doll rise up from behind his bed. Subverted when Tails immediately notices him and punches the doll away off screen.
- Sonic finds Tails lying on the grass and they both run off. They fail to notice Tails Doll lying behind them.
- Promoted to Playable: Entering a secret password in the sequel allows you to play as the Tails Doll. Unfortunately, you can't unlock the passwords when playing as him.
- Sprint Shoes: The speed shoes monitor appears in the sequel. Upon hitting the monitor containing it, Tails' shoes will change from his to Sonic's.