Spike Block

Spike Blocks are blocks originally planned to be introduced instead of Sticky Pistons. They would work like pistons but push out Spikes. It was later suggested to Jeb that he should make Sticky Pistons instead and also make a Spike Block that could be pushed by them. Sticky Pistons were introduced in Beta 1.7.

Uses
Presumably, the Spike Block/Piston would have would have splkes as in the name it will probably caused damage to mobs and the Player, since it would probably hurt mobs or the player it will more lickly be used more on traps than on any other piston cause it does damage.

History
On May 28th, 2012, Dinnerbone stated he wishes to add Spikes to Minecraft, but is unsure how to implement them.

(Forgot the date)In Marc Watson's Deathban Stream him and dinnerbone talked about how the Spikes would have been useful in the castle they made,