Spiny, called Lander (ランダー) in the Japanese manual, is a badnik from the 16-bit version of Sonic the Hedgehog 2 found in Chemical Plant Zone. They move slowly, but can suddenly shoot a bomb out of their upper spikes, so you must still be aware when you approach one.
The enemy reappeared in Sonic Pocket Adventure's Secret Plant Zone, and later returned in Sonic Colours in Asteroid Coaster and Starlight Carnival. In Sonic Colours they cannot be destroyed.
He reappears in Sonic Generations back to Chemical Plant visually similar to Sonic Colors.