Based on snails, Noro-Noros resemble closely the Spikes. They have a pink gastropod shell with three spikes aligned on top of it and a yellow body with a black underbelly. They also have two large black eyes on thin eyestalks, and the sides of their shell are covered in grey bumpy plates.
In Sonic the Hedgehog CD, Noro-Noros are found only in Quartz Quadrant. In gameplay, they squirm slowly back and forth along the ground, but when the player approaches, spikes occasionally thrust out from their shells while they move. The player therefore has to attack the Noro-Noros from the sides with the Spin Attack when their spikes are out.
In the Bad Future or sometimes in the present timeframe of the Rounds, the Noro-Noros show signs of decay: they have lost the plating on the sides of their shell and their spikes. Due to the latter, they cannot use their spikes as defense against the player. Like every Badnik in the game, the Noro-Noros are powered by Little Planet flower seeds which will pop out of them after being defeated.
"Noro-noro" is the Japanese word for "slow" or "sluggish".