From the Super Mario Wiki
Porcupo are black or purple creatures occasionally found in the Mario series. They are said to be a type of porcupine, but actually resemble more of a hedgehog, especially unintentionally somewhat resembling Sonic the Hedgehog.
Super Mario series
Super Mario Bros. 2
In their first appearance in Super Mario Bros. 2, they pace back and forth and are usually in groups of two or more. They can't be jumped on or picked up, so players must throw other enemies or objects at Porcupos to defeat them.
Porcupos reappear in the Super Mario Bros. 2 port included in Super Mario All-Stars . The Porcupos behave exactly the same as in the original, but are purple in colour.
Super Mario Advance 4: Super Mario Bros. 3
The Super Mario Bros. Super Show!
A single Porcupo appears in The Super Mario Bros. Super Show! episode "On Her Majesty's Sewer Service" as the pet of Koopfinger. When Mario and Luigi invaded Koopfinger's hideout though, the Porcupo simply hopped off Koopfinger's lap and ran away instead of trying to fight Mario and Luigi with Mouser, Tryclyde, Vampa White and a Koopa Troopa.
Names in other languages