Mime slows your opponent by requiring at least two turns to be Knocked Out, normally much longer due to Potion and various other stall tactics
So, if you pay 8 mana for this, you will need a total of 18 mana (2 for the initial cost, then the other 8 mana twice)
One way you can do this is by using them as tuners for a synchro summon next turn, allowing you to bring out some seriously powerful monsters to beat your opponent with
Caution There have been confirmed instances of individuals forging sealed box authenticity by removing Wizards logos from the wrapper with alcohol and/or re-wrapping an already opened box with clear wrap in order to increase the boxs presumed value
There's a lot here, and I have a lot of card previews to show you, so get your pen and paper ready, turn on your deckcrafting brain, and enjoy