|This article's title is derived from Japanese|
|...because it was never localized to English in official sources.|
Mega Stactus is a massive green cactus constructed of a head and four body segments. The body is vertically striped and sports four spikes per segment. Its head has two expressive eyes, a smile, a flower, four needles, and two stubby arms with three tiny bumps that act as fingers. Altogether, Mega Stactus' head looks nearly identical to Big Stactus.
Mega Stactus changes colors to yellow and purple as the fight goes on. The color of its flower also changes color where its yellow form has an orange flower, while its purple form has a yellow flower.
Mega Stactus appears exclusively in Stage 3 of Sandy Canyon and the Survival Rush sub-game. The Kirbys enter its room and it attacks immediately. Mega Stactus attacks somewhat similarly to Big Warwiggle; after dust clouds rise, it emerges violently from the dirt ground, attempting to hit the Kirbys on its way up. The dust clouds telegraph where it will appear. If undisturbed, it burrows back into the ground and tries again.
After popping up, the Mega Stactus retracts the spikes on its head. This is the player's chance to flick the Kirbys upward at it. If he/she aims to low, they instead hit the body at take damage. A successful mass attack from at least four Kirbys (or multiple attacks from fewer) brings the head crashing through the body segments down to the ground. Mega Stactus speeds up its attacks and provides increasingly less time to counterattack as it takes damage. It also changes color from green to yellow, then yellow to purple.
After the third crash, the mid-boss's head bounces painfully between the floor and ceiling. It then drifts down, flattened, and explodes.
Mega Stactus' name comes from its enormous size and the name of its species.
Its Japanese name, デカクサン (Dekakusan), is a portmanteau of デカ (Deka), which references it huge size; and カクサン (Kakusan), the Japanese name for Stactus.
- A pre-release screenshot of Kirby Mass Attack depicts Mega Stactus with longer spikes and a pinkish palette.