From the Super Mario Wiki
A Porcupinefish covered in icy water
Mario and Luigi paralyzed by Porcupinefish

Porcupinefish are dark blue spiked fish seen in the first episode of Super Mario World, Fire Sale. They are named after the real-life porcupinefish, a heavily-spiked group of fish closely related to the pufferfish. Due to their appearance, they may be based off the Spiny Cheep Cheep or the Porcupuffer, though they more closely resemble Urchins. They pop out of the water, sometimes from beneath sheets of ice, to stab people with their paralyzing spines. Throughout the episode, Mario, Luigi, Princess Toadstool, and Kootie Pie are paralyzed by Porcupinefish.