This is the dankest copypasta on the Internet right now.
The moves aren't important for this one—the item is. Ferrothorn is a fantastic entry hazard setter that has some valuable defensive properties in checking Pokémon like Ash-Greninja, Magearna, and Tapu Koko. However, one of its main downsides is its lack of reliable recovery, which makes it vulnerable to being worn down over time. Using Rocky Helmet makes this problem even worse, as it doesn't get the passive recovery it desperately needs from Leftovers. The appeal of the item is of course the good chip damage it can incur alongside Iron Barbs, but Ferrothorn generally doesn't switch into many Pokémon that use contact attacks, and it is already good at dealing chip damage with Iron Barbs, hazards, and Leech Seed.