It's been used by various Pokemon throughout the generations, including:
* Slowbro (in Gen 1 and 2)
* Mr. Mime (in Gen 2)
* Tauros (in Gen 2)
* Girafarig (in Gen 2)
* Whiscash (in Gen 3)
* Lickilicky (in Gen 4)
* Stoutland (in Gen 5)
* Exploud (in Gen 6)
* Drapion (in Gen 4 and 5)
It's a risky move, but it can be very effective if used correctly. If your Pokemon is not confused, it will have a major offensive boost, but if it is confused, it might end up hitting itself!