Found this monstrosity in an old sudoku magazine. It consists of 3 overlapping irregular Killer-Sudokus where the blue squares must be even numbers and the orange squares are uneven. On top of
Chaos Hexadoku puzzles - 16x16 Chaos Sudoku - to play online.
Chaos Sudoku Ser.: Chaos Sudoku 12x12 - Schwer - Band 18 - 276 Rätsel by Nick Snels (2015, Trade Paperback) for sale online | eBay
Solving Irregular Sudoku
Tellurium Chaos — Rätselportal — Logic Masters Deutschland