This is an add for the app (like for phones and tablets) for Sonic Dash. It says "For a limited time only take on Zazz in an epic boss battle". (From Lost World, of course!) In the special area, he rolls his evil ball around & it appears to have Sonic chasing him. However, the actual game/level was different than what's shown here, in that it ended up having no icons, and the whole thing goes in a streight line (while corners are shown here)
Why is it different? The iphone & android apps use a different layout for the level.