What does Ditto copy?

Question

I thought Ditto copies everything, but I was doing an Uber battle on Showdown and my opponent used Xerneas with power herb. I sent out an Impostor Ditto to copy them, and it's holding a choice scarf, so I should OHKO them right?
Wrong - I only do around 75% damage to them, then they use the same attack (Moonblast) and OHKO me! Does Ditto really copy everything? Is it a glitch in Showdown? Thanks! (if you need I can post the replay)

Answer 1

The reason that happened is because Ditto copies every stat other than HP, so the foe's Xerneas had more HP.

Ditto uses the move Transform to copy the opponent's moves, types,
form, and non-HP stats

Source

Comments

Oops that's the one thing I misread :P