Tonic Adventure is the cancelled sequel to Tonic Trouble, a 3D platform game developed by Ubisoft Montreal and Ubisoft Montpellier, released in mid 1999 for N64 and PC. Tonic Adventure was being made from 1999 to 2000 (perhaps for Dreamcast or the soon-to-be-released PS2) by the same team that worked on the original game and Rayman 2, but it seems that the project was canned in early development, maybe because of low sales and mixed reviews of the first TONICT. Only a few concept arts were found in the portfolio of a former Ubisoft artist, preserved in the gallery below to remember this lost game. We can speculate that after Ubisoft found out that Tonic Trouble would have not been a popular IP as they planned, they switched resources from Tonic Adventure to more marketable games as Rayman M and Rayman 3.
If you know someone that worked on Tonic Trouble 2 and can help to preserve more info about this cancelled project, please let us know!
Thanks to Maxime for the contribution!