Spynum is a shifty bipedal enemy. It has a blue body and an indigo head with white eyes and no mouth. The enemy has crimson feet (brownish-purple in-game) and floating, spherical, yellow hands that uniquely have thumbs. It wears a purple cloak and a crimson hat to keep its identity masked. The hat is adorned with a rainbow feather on its left and right sides. Spynum carries its red bow on its back when not firing an arrow.
An insect variant of Spynum, known as Sectra Shooter, appears in Kirby: Triple Deluxe only, and is encountered in Royal Road. Sectra Shooter's build vaguely resembles Spynum's appearance, having a green body and head, a light green facial area, as well as light green, spherical hands and magenta feet that, unlike the common variant that have round feet, have two toes. It has large, yellow-orange, insectile eyes, with what appears to be a magenta band around its head instead of a hat, but the top of its head still resembles one in shape. It also has indigo antennae and bow.
Additionally, it wears a pink cloak with a painted pattern; having indigo spots lower down and longer, more vertical magenta spots higher up.
Spynum rarely moves. It holds completely still until Kirby approaches. The enemy quickly lifts the brim of its hat, pulls out its bow and arrow, and fires a well-aimed arrow at the hero. It immediately returns its bow to its back and lowers the brim of its hat.
Most Spynums are positioned on Star Blocks or other high platforms, giving them a good range from which to snipe Kirby. A few Spynums in the game walk around when Kirby is away. Most Spynums attack the hero from the foreground, but some stand in the background and shoot arrows at him from there.
In Kirby: Triple Deluxe, insectile versions of Spynum, known as Sectra Shooters, appear in Royal Road. They act the same way as Spynum.
Spynum never fires arrows from the background in Kirby: Planet Robobot.
Spynum's name is derived from the word "spy," describing the enemy's shady appearance.
Its Japanese name, スパイナム (Supainamu), may also be an anagram of "sniper," スナイパー (Sunaipā), albeit with the prolonged sound mark (ー) replaced with mu (ム); スナイパー (Sunaipā) is also the Japanese name for Archer, the Copy Ability the enemy gives.
- As illustrated in Spynum's artwork, it is one of the few enemies in the Kirby series to have thumbs.