Spike

A spike is an attack in in the Super Smash Bros. series and Super Smash Flash series that sends an enemy straight down at high speeds. Spikes cannot be Meteor canceled by jumping while you are plummeting down, or else they are named a Meteor Smash.

Here are some characters with spikes:

Mega Man 
 * Down Aerial - Mega Man bends over, making the top of his head visible. He extends his arms outward, sending a powerful shock wave under him. Anyone in contact with him or directly under him is sent downwards at a very fast speed and cannot jump or recover until the hitstun wears off, making this the strongest spike (at 0%, also) in the game.