Hydreigon would like a word with you.

FUN FACT: It seems that most - if not all - Dragon-type Pokemon are capable of learning a Steel-type or Poison-type move. In particular, Hydreigon's use of Flash Cannon can be used to trick your enemy into switching to a Fairy, only to punish them with a super-effective attack. Unless it's Mawile or Klefki. In which case, Hydreigon also learns Flamethrower.