Nail

Nails are peg-like objects appearing in certain 3D Mario platformer games. They can usually be clung on to for the player to jump off of.

Super Mario Sunshine
Nails first appear in Super Mario Sunshine, appearing only in the Pachinko Game area. They can be stood on like regular platforms, but have a limited hitbox.

Super Mario Galaxy
Nails also appear in Super Mario Galaxy, specifically in the Deep Dark Galaxy missions Boo in a Box and Bubble Blastoff. They must now be clung on to, and provide a very limited range for the player to jump off of.

Super Mario Galaxy 2
Nails return in Super Mario Galaxy 2, specifically in the Clockwork Ruins Galaxy mission Time for Adventure. They behave as they did in Super Mario Galaxy.