Freezie

A Freezie (originally known as a Slipice) is an enemy made entirely of ice that first appeared in the arcade game Mario Bros. They vary greatly in size and shape, but are instantly recognizable thanks to their permanently puzzled expression. Occasionally, Freezies are used as items to (obviously) freeze enemies. Despite being one of Mario's first enemies, they have only recently started appearing in games again. They don't appear in other regular Mario games.

''Mario Bros.
In the original Mario Bros., Freezies emerge from pipes and travel along the stages' platforms (just like other enemies). They first appear in Stage Nine (Stage Ten in Japan). When a Freezie reaches the center of a platform, it will coat the entire platform with ice, destroying itself in the process. A frozen platform is very slippery. Thus, it is in Mario and Luigi's best interest to eliminate these enemies quickly, before they can freeze a platform. It can freeze the central floating platform and the two lower platforms above the bottom pipes. If all three platforms are frozen, no more Freezies will appear for that phase. Hitting a Freezie from below destroys it and awards the player five hundred points. Freezies don't count as regular enemies, meaning Mario and Luigi don't have to clear them from the stage to complete the level. If Mario or Luigi touch a Freezie, they will lose a life, but the Freezie will only reverse direction.

Freezie is the only recurring enemy from Mario Bros. that has kept its Nintendo Entertainment System name rather than its original Arcade name.

Super Smash Bros. series
The first game outside of the various Mario Bros. remakes to feature Freezie. They are used as items in both Super Smash Bros. Melee and Super Smash Bros. Brawl, randomly appearing on the stage. When a Freezie appears, it will slide across the stage until picked up by a character, falling off the stage, or broken. Freezies in Melee break after a single attack is used on them, provided the attack does damage, while the ones in Brawl are a bit more resilient. Upon being picked up, the Freezie can then be thrown at an opponent, encasing the opponent in a block of ice. While frozen, the opponent will be defenseless for a few seconds, allowing other characters to mercilessly attack the incapacitated foe. The larger the opponent's damage, the longer they will be trapped. If an opponent is knocked-out by a thrown Freezie in Melee, the player receives a "Freezie KO" Bonus. Additionally, the Freezie appears as a collectible trophy.

''Mario Kart: Double Dash!!
Freezies also appear in Mario Kart: Double Dash!!. Large, stationary Freezies are located on the ice lake at the end of the racetrack Sherbet Land. If a character drives into a Freezie, their kart will become frozen in a block of ice for a few seconds. After being hit (by kart or item), a Freezie will slide along the ground until it hits a wall and shatters. However, a sliding Freezie can still freeze any karts that it runs into.

Mario Party series
At Snowflake Lake in Mario Party 6, Freezies appear during the night blocking players from other paths. In the minigame Frozen Assets from Mario Party 8, Freezie rises, and then slams back down into the icy arena, causing big icicles that contain gems to fall onto the ground.

''Mario Pinball Land
In this game, a Freezie appears in Frosty Frontier. On the second screen of this stage, a Freezie can be found sitting in the middle of the screen while penguins walk around it. Mario must hit this Freezie, pushing the ice creature over a crack in the ice. This then creates a hole that leads to the boss area.

''Mario Power Tennis
Freezies appear as a rare obstacle in Mario Power Tennis. On the Mario Bros. Classic stage, the original sprites for enemies are used (instead of modern sprites). When playing a Gimmick Match, Freezies will occasionally slide onto the court and freeze half of a characters play area. Hit the POW Block to stop it.

''Dance Dance Revolution: Mario Mix
Additionally, Freezies make an appearance in Dance Dance Revolution: Mario Mix. In the game, a gigantic Freezie is the boss of World Four and the keeper of the fourth Music Key. In fact, the key is lodged in the huge ice creature. This giant Freezie resides on the top of a snow-capped mountain and is surrounded by normal (and much smaller) Freezies. When Mario (or Luigi) and Toad arrive to retrieve the key, Toad politely asks the giant Freezie to return the musical item. However, the Freezie does not respond. As such, Toad tells Mario to melt the giant icicle with his burning hot dance moves. As Mario starts dancing, the giant Freezie (who recognizes the seriousness of the word melt) attempts to block Mario's dance steps with ice. However, the dancing master Mario counters by activating Fire Flowers to keep his hot beat alive. Eventually, the giant Freezie melts away into a puddle of water and Mario recovers the last Music Key.

''Mario Hoops 3-on-3
In this game, Freezies only appear in the Sherbet Land stage. A character can grab this item and throw it at an opponent, who is frozen for a short time after being hit.

''Mario Super Sluggers
Freezies appear as stage hazards in Peach Ice Garden, sliding around on the ice. One is also seen crashing into Toad while he is trying to catch a baseball in the game's introductory cut scene. Fortunately for Toad, Blue Toad appears and accidentally slips, crashing into the Freezie and freeing Toad.

Trivia

 * In Super Smash Bros. Brawl when a Freezie hits an opponent, it makes the same sound effect that was heard when a Freezie gets defeated in Mario Bros..
 * Freezies might be related to Li'l Brrr.