Buried
Buried is a state in Super Smash Bros. Melee, Super Smash Bros. Brawl, and Super Smash Bros. 4 that characters enter when hit by an attack that induces the bury status, including Headbutt, Earthquake from Togepi, Wii Fit Trainer's Natural combo with 3 weak attacks or a Pitfall. In this state, controls are disabled until it wears off (this point being where the once buried character will get some invincibility frames). While buried, the character can not be grabbed. Like other status effects, button mashing reduces its duration.
The amount of time a character remains buried is dependent on that character's damage percentage; the higher the number, the longer they will be stuck to the ground.
Characters can only be buried if already standing on the ground; moves that bury will usually meteor smash airborne opponents.
In Melee, buried characters cannot be "unburied" by getting hit; they will remain stuck in the ground until the effect wears off. However, in Brawl and Smash 4, a character that takes a hard enough hit will be relieved of the bury effect and sent flying, though with less knockback than normal.
Gallery
Luigi buried in Super Smash Bros. for Wii U.