Unstable Mutation is actually potentially rather funny with Remove Enchantments because you can play an Unstable Mutation on your opponents creature let it get a -1/-1 counter or two, and then return the Mutation to your hand, to play on one of your own creatures
This is really giving me True ConvictionTrue Conviction vibes
BT7-064 U Digimon Lv.5 DoruGreymon Color Black Cost 8 DP 7000 Digivolve Cost 1 Black 3 from Lv.4 Form Ultimate Attribute Data Type Beast Dragon/X-Antibody Card Text 1 [Effect] [When Digivolving] You may place 1 black card with [X-Antibody] in its traits from your hand at the bottom of this Digimon's digivolution cards to prevent effects from deleting it or reducing its DP until the end of your opponent's next turn
Now this is a golden fish worth catching
However, it did so not through a retrain but by adding new cards that support the OG
(When an opponent's Digimon attacks, you may suspend this Digimon to force the opponent to attack it instead.) BT11-032 SR Digimon Lv.6 UlforceVeedramon Color Blue Cost 12 DP 12000 Digivolve Cost 1 Blue 4 from Lv.5 Form Mega Attribute Vaccine Type Holy Warrior/Royal Knight Card Text 1 [Effect] [When Digivolving] You may play 1 blue Tamer card from your hand without paying the cost