Lion is a game for the Game & Watch console. It appears as Mr. Game & Watch's forward tilt in both Super Smash Bros. Melee and Super Smash Bros. Brawl, as well as a "stage" within Flat Zone 2 and a sticker.
As a stage
In Lion, the aim of the game was for two players on either side of a cage to keep a lion from escaping by using chairs, making the game very similar to Pong. As the game progressed, multiple lions would be in the cage. With this inspiration, Lion was incorporated as one of the changing stages played within the Game & Watch system in Flat Zone 2 (along with Fire, the default; Chef; and Oil Panic). The lion cage would encompass most of the stage, with two Lion Tamers on either side, attempting to repel the brawlers back into the cage. The Lion Tamers' chairs both have massive knockback, and it is not uncommon for players to be juggled between the two. Thus, it is strategic for a player to attempt to throw or knock their opponent into one of the Lion Tamers for easy KOs (which are made easier by the notoriously close blast lines).
Back in the day, there were a lot of kids into the Game & Watch series. Quite a few adults as well, honestly. This game was a popular pick, with players controlling two zookeepers as they tried to keep the lions from escaping. The built-in clock was great for keeping track of your time spent playing!