Ultrex io is probably the weirdest Agar io mod. The idea of the game is crazy itself. Let's try it
How to Play
At the beginning of Ultrex io you begin as big fat cells. You can't even notice the motion. Split your cell by clicking A or D to gain some acceleration. After splitting the cell will merge back again. Try eating other players. Seems impossible though.
Well the gameplay of Ultrex io is unique, no doubt. Maybe you will love it more than the classic Agar io. However if you found the game interesting, but the idea not that attractive, you can try classic Petri Dish game. Also note the multiple videos about this type of games.