Mist Ball is learned by 1 species by level

Effect, in PokéAPI's words

“Has a chance to lower the target’s Special Attack by one stage.”

Who learns it

1 species in all, 8 of 17 games shown

Scarlet and Violet: 1 species

Species	Method	Level
Latias	Level up	35

Brilliant Diamond and Shining Pearl: 1 species

Species	Method	Level
Latias	Level up	35

Sword and Shield: 1 species

Species	Method	Level
Latias	Level up	35

Ultra Sun and Ultra Moon: 1 species

Species	Method	Level
Latias	Level up	24

Sun and Moon: 1 species

Species	Method	Level
Latias	Level up	24

Omega Ruby and Alpha Sapphire: 1 species

Species	Method	Level
Latias	Level up	24

X and Y: 1 species

Species	Method	Level
Latias	Level up	35

Black 2 and White 2: 1 species

Species	Method	Level
Latias	Level up	35

Changed over time

One change since Generation III

1. Through Gen VIIIPower 7095 from Scarlet and Violet, Generation IX