Mountain Hands was supposed to be one of Ben's original Team Tennyson aliens, but was replaced by GoldFreak. Some of his powers include super strength, and a cool power that he can make sonic waves with his hands, like Four Arms.
Unlocking
Mountain Hands was finally unlocked by Ben in Where There's Charm, There's Hex. Ben used him to take down Hex, but that wasn't the end of Hex. Ben used his sonic waves to destroy the Mountain Monsters.
Species and Homeworld
Mountain Hands species is called the Cabeças de pedra. They are also home to Gargoyle's species, the Pedras. Their planet is called the Espace Lua, which Is similar to the Earth's moon, but much bigger.
Ultimate Team Tennyson
In Ultimate Team Tennyson, Mountain Hands stolen from him by Albedo in Can Mountains Jump?. Albedo put him in a rocket and launched him to Petropia. Later in King Of The Mountain, Ben gets a tip from Sugilite that he had found Mountain Hands. When Ben goes to the planet, he finds out that Albedo turned him evil. After a huge fight, Ben scans him, and goes back to Earth.