Diabolical is a completed TF/TG transformation text adventure game created by Cleo Kraft.

A text adventure game written in Tads 3 for the 2010 Halloween Contest on the TG/TF Transformation Games website.

The main character is Jake, off on vacation to a village beside a mountain lake. While there he discovers rumors about transformation machines, shrink rays and all kinds of fantastic things happening at the island in the middle of the lake. He gets dropped off by a hired boat ride and begins the game on the dock of the sandy shore.

The game has adult themes including sex change transformation and should only be played by adults.

2.00 - Updated 28JUN2019 - Added some startup options: Player first name, skip intro, show exit links in room description. Fixed a few bugs in the ending. Added a few more decoration objects the player might refer to in some locations. Worked out a way to get past the dragon in the "easter egg" cork path. Began work on a built-in bonus game if you manage to get through to a "win" ending.