Giant spear

Spears are objects that they scretch up and down. Although the spears were use as weapon in Sonic Heroes and Shadow the Hedgehog.

Sonic the Hedgehog (16-bit)
The spears appear in the Labyrinth Zone.

Sonic the Hedgehog (16-bit)
They appeared in Metropolis Zone where they three of them in a box where each of them will pop in and out in different way.

Sonic 3D Blast
They appeared in Spring Stadium Zone, the spears were seen block Sonic's way where you need to get Flickys to unlock the Giant ring to open them. They also appear as obstactles if Sonic steps on them they will rise up and damage you.

Sonic Heroes
The spears were use as weapons for Egg Pawns.

Shadow the Hedgehog
The spears appear again as weapons for Egg Pawns.

Sonic and the Secret Rings
The spears appears as object that fall straight at you in Sand Oasis.

Sonic the Hedgehog 4 Episode 1
They appear in Lost Labyrinth Zone where they do the same thing they did in the first game.

Other Media
In Adventures of Sonic the Hedgehog episode "Sonic Breakout" the spear was use as a harpoon.