- You may be looking for Hot Pursuit (Classic).
Hot Pursuit is the second Challenge Act of Speed Highway Act 2 in the console/PC version of Sonic Generations. It is unlocked after clearing every Stage in the Dreamcast era and is playable only as Modern Sonic.
This Act takes place within a slightly modified section of Speed Highway Act 2, with several additional platforms scattered throughout the stage.
In this Challenge Act, the player has to chase a Sprinkler enemy, who drops rings as it moves along the course. The player needs to collect at least one hundred of these Rings before making it to the Goal Ring in order to complete the challenge, while avoiding the other enemies as well as the occasional bomb dropped by the Sprinkler. There are numerous sections where the Sprinkler will stop and drop a large number of Rings in the general area, which should be quickly collected before they disappear. Sonic otherwise must traverse shaky platforms and continue through the Act has he normally would in order to proceed.