Mimic is a Light type move. It consists of copying the last move the target used and replacing its slot with that move for the rest of the battle. Note that this will not work if the Ponymon using it already knows the move that is being mimicked as no Ponymon can know the same move twice; you will receive a "But it failed" message every time it is attempted in this instance.
"The user copies the move last used by the foe for the rest of the battle."
DISCLAIMER: More ponies may need to be added with further expansions.