Totem

Totems are green pillars animated by the vile power of Medusa. They are found in the Palace in the Sky. They fall from above, like Rokman, but in a column formation.

Kid Icarus
"A pillar in the Palace in the Sky turned into a monster by Medusa. They fall down from the ceiling and pile up on each other."

Totems, falling in groups of four, will only stack if they land on the red-brick platforms.

Kid Icarus: Of Myths and Monsters
"Animated blocks which suddenly fall from the ceiling and pile up."

Totems often stack in columns of five; more will appear to replenish the stack if individuals are killed. Totems can fire a projectile straight ahead, but only one projectile may be fired at once, no matter how many Totems are there, and usually only the bottom three Totems will shoot. No longer restricted to just the Palace in the Sky, they're now often found guarding Hot Springs. Though Totems can be used as a platform, Pit will suffer damage by stepping on one.

Trivia

 * The Totem likely served as inspiration for an enemy called Stackjaw in Kid Icarus: Uprising.
 * Despite being blue in the Kid Icarus manual, Totems appear green in the game itself.