I lost my whole Lvl 60+ Team: The frustrations of being a pokémon master

[Maxpphire]

Actually Missingno's sister glitchmon, 'M was known to cause more damage to the game then Missingno and was much more dangerous. They have the same sprites and are easy to confuse. Anyway 'M is known for freezing the game if you attempt to remove it from the PC. So you might have had an 'M and not a Missingno.