If I counter a planeswalker what happens to them?
A planeswalker is a spell while it is on the stack. Any spell you counter will go to the graveyard unless the counterspell says otherwise, such as with Remand. Thus, a planeswalker will be put into the graveyard. Not sure if this is a question confused on whether planeswalkers are treated differently than other spells or not? If you had some other reasoning why you think a planeswalker might be treated differently than another spell, feel free to add it to your question! It may help newer players to understand it better in the future.