Sakurai has taken to Miiverse to deliver the picture of the day and the following message:
Pic of the day. This may look like a side-scrolling action game, but it's actually one of the stages.
What exactly is this stage from? That is the question you are probably asking, unfortunately I can not say as I have no idea either. Speculation of this stage suggests a potential link to the Legend of Zelda or even Kid Icarus Uprising based on one of its levels. At this point in time I would be inclined to believe anything, as all we have right now is speculation perhaps the spring even referencing that this is the Sonic stage. I could be wrong however and it have no link to any of my thoughts. The message though does incline me to consider that this stage is linking to a side scrolling action game and perhaps this stage is a link to the classic roots of a franchise. Again I have no clue and this is merely all my thoughts, but still it is safe to say that this stage does look pretty cool and potentially deadly.
If you missed yesterday's picture of the day you can find it here. It had an interesting picture of Luigi and what looks like his Final Smash.