So, according to Serebii...
...the move it learns at Level 62 is "Simple Beam" and changes the target's ability to Simple.
In Singles? Don't touch this. Nine times out of ten, Simple is a boon to the target.
In Doubles or Triples?
Imagine a speedy Genosect paired with a setup sweeper. Genosect Simple Beams Ononokusu, Ononokusu DDs, next turn things start dying.
The possibilities are endless... Well, if it doesn't do damage, anyway.