Magnet is your ultimate power-up while playing in a level.
To fill the magnet you need to blast rows and columns. Each score you make will fill the magnet. When it is full, the word MAX will appear on it and it will be ready to use. When you use the magnet, all the squares spread on the board will be aligned from the bottom to the top of the board, eliminating the gaps between them. This frees up more space and allows you to reach new combos more quickly.