Aron

Thanks to Rock Head, Aron has access to a recoil-free 150-Base Power STAB move in Head Smash, which hits hard thanks to Aron's solid base 70 Attack. A great base 100 Defense allows Aron to survive strong physical hits, especially when coupled with an Eviolite. Its Steel / Rock typing gives it useful resistances, most notably to Fairy- and Flying-type attacks. However, its typing also gives it very common weaknesses to Water, Ground, and Fighting. Head Smash also has very low PP. It's difficult for Aron to set up on many things due to coverage moves such as Earthquake from Snubbull and Jump Kick from Doduo. Aron also has low Special Defense, meaning it can have a tough time switching in on special attacks. It faces competition from other setup sweepers that can be stronger and faster than a set-up Aron; Shell Smash users like Tirtouga and Shellder are particularly good examples. Aron also has very low Speed prior to a Rock Polish, meaning it can be KOed easily if it hasn't set up.