I remember as a kid playing Silver, I caught a Smeargle and tried using Sketch. Unfortunately, it somehow missed, and as it only had 1 PP, Smeargle was forced to struggle.
How can this happen? I've been trying to find information online, but I haven't been able to find a single mention of the possibility of Sketch missing or the circumstances under which this happens. Does anyone know?
Best Answer
Sketch will fail if Smeargle moves first in a battle. Simple, if there is no move for Smeargle to Sketch it can't Sketch it.
However there are other situations where Sketch cannot copy a move. This list has changed over the generations however. To use your example of Silver, from Generation II:
As of the current Generation (6), Sketch cannot copy Struggle or Chatter, and will fail if the opponent uses Crafty Shield
Source: Bulbapedia