Lincoln West
Lincoln was able to see reasonably clearly thanks to his goggles keeping his eyes free from the sand. So when he spotted Verno cloaked in flame, charging towards Bixi, he had plenty of time to react.
"Bixi, take the hit, then Aqua Tail!"
Following Lincoln's instructions Bixi took the attack from Verno, wincing from the impact and the flames. Flame Wheel was a physical attack, so Sandstorm didn't help with it, but her double resistance and defensive nature still helped to mitigate the attack. As she was reeling from the strike Bixi used the momentum to spin herself around, her small tail becoming surrounded with swirling water from her shell. Provided the attack stayed on course Bixi's hydro-empowered tail would strike Verno.
If John hadn't already guessed then it would become fairly obvious now that the turtle pokemon was not only a rock type, but also a water type.
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Jackson (Male Shieldon) Lvl 24: Toxic, Sandstorm, Protect, Iron Head, Stealth Rock, Dig
Ability: Sturdy
Bixi (Female Tirtouga) Lvl 24: Crunch, Aqua Tail, Sandstorm, Ice Beam, Stone Edge, Iron Defense
Ability: Solid Rock
Siege (Male Geodude) Lvl 22: Defense Curl, Attract, Rock Polish, Rock Throw, Magnitude, Roll Out
Ability: Rock Head