Glistas

Well, was that supposed to be a bug or a feature?

As Seen Below, My Forretress doesn't know the move "Spikes". When I took it to the move relearner, it showed me all the moves other than spikes. I am attaching 3 screenshots showing the list of moves the relearner is showing. Please help me fix this. I spent a long time raising this forretress, and I want spikes.