Icicle

Icicles (Japanese, ツララ tsurara) are pointy pieces of ice, in both the real world and the Mushroom World, that have sometimes appeared in the Mario series. These icicles are far bigger than their real world counterparts, often as big as or bigger than a human.

Appearances
They first appeared in Phase 16 (17 in Japan) of Mario Bros., as obstacles that attacked by dropping from under the top platforms and pipes where they constantly regenerate. They would also kill the player if they touched an icicle while it was still attached to the ceiling. Touching it while it is still a liquid droplet or using the POW Block will prevent the icicle from being formed though this will not award any points. However, the POW Block will also cause fully formed icicles to drop prematurely.

In Super Mario Bros. Special, icicles could be defeated by fireballs. They do not regenerate.

In Super Mario World 2: Yoshi's Island, whacking an egg at them would cause them to fall down from the ceiling.

Wario has met icicles as well in Wario Land: Shake It!, in the level Slipshod Slopes. They appear in a cove part, and seem to be gigantic. When executing the Earthshake Punch, these big icicles will fall down, and crush any enemy underneath (defeating 5 enemies with those icicles is also a mission in that level). When Wario hits a falling icicle, he'll get hurt. Wario can also stand on those icicles as if they are platforms. However, the fallen icicles will break after a short time. when broken, new icicles will grow on the piece of ceiling the old ones were fallen off. There are giant icicles as well in Freezing Fields.

The reappeared in Super Princess Peach and behaved the same way as they did in Mario Bros.

They also make a minor reappearance in Super Smash Bros Brawl. When Fighting in The Ice Climber's stage, they act the exact same way they did in Mario Bros. (game) except they are invincible and cannot be melted this time

They are found in 3-3 and 3-Castle of New Super Mario Bros. Wii along with giant falling icicles that Mario can walk on. Icicles come in different sizes. When an icicle falls another one forms unless it is a giant icicle. If the player gets hit by an icicle, it has the same effect as getting hit an enemy. A similar obstacle is the Falling Spike in Super Mario World however Falling Spikes attack due to proximity as opposed to maturity.