We don't know if there will be a happy ending in the season finale of How I Met Your Mother, but there will be a cast member of Happy Endings in said finale. Vulture has learned that Casey Wilson (Penny!) and Key and Peele's Keegan-Michael Key will appear in the last episode of HIMYM's eighth season, airing in just a little over 45 days (May 13, to be exact). Our sources say Saturday night sketch comedy alumni Key (MADtv) and Wilson (SNL) will guest-star as a couple having dinner at the same restaurant as Robin and Barney. Could either or both characters have any impact on the pending Stinson-Scherbatsky nuptials? Will Wilson end up being Ted's musically inclined future bride? Are we just throwing out random questions to which we don't know the answer as a distraction to cover up the fact that we know hardly anything about why Wilson and Key are on the show? The answer to all three questions: maybe!