As long as Gliscor is your Active Pokémon, your opponent can't remove any Special Conditions by evolving or devolving his or her Pokémon. (This also includes putting a Pokémon Level-Up card onto the Pokémon.)
Flip a coin. If heads, put damage counters on the Defending Pokémon until it is 10HP away from being Knocked Out. If you do, shuffle Gliscor and all cards attached to it into your deck.