What does endeavor do in Pokemon sapphire?

"Endeavor" is not a move in Pokemon Sapphire (or any other main series Pokemon game). It is a move that was introduced in Pokemon Diamond and Pearl, and is learned by the Pokemon Meditite and Medicham.

Here's how Endeavor works:

* Endeavor lowers the user's HP to match the target's current HP.

* If the user's HP is already lower than the target's, the move fails.

* This move is primarily used to set up a guaranteed OHKO (one-hit knockout) with a move like Fake Out or Extreme Speed.

In Pokemon Sapphire, you might be thinking of a different move. Could you please clarify which move you're referring to? Let me know if you need help remembering its name, or if you're interested in learning about other moves that have similar effects.