Ambush

The Yoshi Team ambushes the player in Melee.

An ambush in The Research Facility I. Note the typical "ambush design" of the place battled in, and the slight dark fade.

The Canyon, a level consisting solely of an ambush with an enemy counter.

An ambush or a locked battle is when a side-scrolling level stops having the player continue forward and locks in place, forcing the player to take on a group of enemies. Once all of the enemies are defeated, the player can resume advancing through the level. They exist in order to keep players from simply running through every level without engaging any enemies.

Ambushes first appeared in Melee's Adventure Mode, though they are present in three stages: Mushroom Kingdom, the Underground Maze, and Infinite Glacier. In the Mushroom Kingdom, the player must defeat the Yoshi Team before they can continue forward to complete the level. In the Underground Maze, the player is tasked with finding the Triforce within the maze; some areas that can contain the Triforce, however, may instead feature the Master Sword in its pedestal, and landing in these rooms causes the player to encounter Link. In Infinite Glacier, a team of two Ice Climbers ambush the player when they have survived traversing Icicle Mountain for a sufficient period of time.

Ambushes became considerably more common in Brawl's Subspace Emissary, with every level containing at least one ambush. They can be identified by a purple screen flash and a distinctive sound, followed by a series of enemies appearing on a specially-designed part of the level, as well as a slightly darker border around the screen; when an ambush is over, the screen flashes white with another distinctive sound, and the player usually receives a reward of some sort, often in the forms of stickers, though recovery items and trophies can also potentially be awarded. Certain levels - namely Midair Stadium, The Battlefield Fortress, The Canyon, Outside the Ancient Ruins, and The Subspace Bomb Factory II - have situations similar to ambushes except for the fact that the battle takes up an entire piece of the level, instead of being a blockade in the middle of a level. These ambushes generally have a higher enemy count, alongside an extra display on the screen showing how many more enemies remain. The Canyon is made up entirely of an ambush, and is the the only level to consist of such.

Ambushes can also happen in certain areas of the Smash Run map in Super Smash Bros. for Nintendo 3DS. When ambushes occur, the player is tasked with defeating a number of enemies within a period of time; if they defeat the enemies before the timer runs out, they will receive stat boosts, as well as other potential rewards, such as trophies. Failing to defeat all the enemies within the time limit, however, does not grant any bonuses.

Trivia

• Unlike other ambushes, fights with Link in the Underground Maze are not initiated until the player is grounded. As a result, it is possible to complete the stage without ever having to take part in a fight with the character, though this precludes the player from receiving the Link Master special bonus.
• For most ambushes, parts of terrain that are not connected to the main area and are just off-screen become disabled, preventing players from being rescued by a bounce off of an unseen object.
• Glires, Glices, and Glunders tend to take themselves out of ambushes, due to rolling along terrain that leaves the screen.
• Humorously, there is a locked battle in Subspace (Part II) that contains nothing but a Ticken - which appears above no platforms and promptly falls off the screen.