These Vanillish are three ice-type Pokémon owned by Brycen.
Brycen used his three Vanillish in a training session against Black's Tula, Musha and Costa to make them stronger.
Brycen stood with his Pokémon, including his three Vanillish, as Black reached him in his Gym. Brycen used one of his Vanillish in his gym battle against Black and his Emboar after he defeated his Cryogonal. Vanillish used Hail which hit both Black and Bo. Vanillish used the Hail to hide itself from Bo, but he was able to attack Vanillish with Head Smash, but that wasn't enough to defeat Vanillish. Due to a combination of Hail and the Head Smash recoil, Bo was frozen and defeated, leaving Black switch out Bo for Musha. Musha used Psychic but that wasn't enough either to defeat Vanillish and Vanillish was able to defeat Musha somehow. Black then recalled Musha and used his Costa as his next Pokémon. Costa used Scald which was enough to defeat Vanillish due to Scald being hot enough to melt the ice of its body.