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 been used in traps, therefore they would probably have caused damage to mobs and the Player.

History
En person kalled Notch den 1. boldede en dag med en person de rhed noar