[Start of Your Turn] If you have 2 or less memory, set it to 3. [Your Turn] When any of your Digimon with the [Rock Dragon] or [Machine Dragon] trait are played, by suspending this Tamer, 1 of your level 4 or higher Digimon may digivolve into a Digimon card with the [Rock Dragon], [Earth Dragon], [Machine Dragon] or [Sky Dragon] trait in the hand with the digivolution cost reduced by 2.