Smogon Forums

Gen 5+:
- Only Sketch, Struggle, Chatter, and Z-Moves are hardcoded out
- Selfdestruct/Explosion fail with Damp, Memento fails if the target already has -6/-6, Healing Wish/Lunar Dance fail if there's no one to switch in, Final Gambit fails (and doesn't self-KO) if the target is a Ghost

- Mirror Move and Mimic fail if no move has been used yet, Transform fails when used on a transformation, Metronome fails on a faster Pokemon using Taunt
- In general, a setup can be done with either a Double Battle or letting Ditto transform into another party member

Gen 3-4:
- It looks like Metronome is only Sketchable if it fails because a faster Pokemon drains its PP to 0. If selected and then blocked by Taunt, it won't count as the "last move used".

Gen 2:
- The move has to succeed, be used last, and still be in the target's moveset for Sketch to work, so Sleep Talk, Mirror Move, Mimic, Transform, Metronome, Selfdestruct, and Explosion are all impossible to Sketch.

- (Sleep Talk, Mirror Move, and Metronome can't call themselves, Mimic can't mimic itself, and transforming into a target that also knows Transform doesn't work either. There's no Damp to stop Selfdestruct/Explosion, after which the target isn't there anymore.)
- No Double Battles means letting an opposing Ditto transform becomes the main setup option.

In gen 2 you mentioned that a move has to succeed, be used last, and be in the targets moveset to be sketched. In gen 3+ is it just changed to "has to be used last"?