Gnarantulas are cloud-covered arachnids found in Mario & Luigi: Partners in Time, found in the skies or caves in Yoshi's Island. Their name is a portmanteau of the words "gnaw" and "tarantula," though they more closely resemble ants, having only four visible legs, sideways jaws, and two antennae. Only Baby Mario and Baby Luigi can encounter them, as the areas they are located in can only be accessed by them via trampolines in the overworld. The cloud hides their body; when attacked, a Gnarantula's unmasked form is revealed. In fact, there are two types of Gnarantulas: the green, spiked Gnarantula, and the red, spike-less Gnarantula. Since there is no way to tell which kind of Gnarantula one is without attacking, it is recommended that they should be hit with a hammer and other attacks rather than a jump so the player does not end up taking damage from the spikes of the green Gnarantula. The green variety is vulnerable to fire attacks, while the red variety is vulnerable to ice. To attack, a Gnarantula jumps, then jumps again in mid-air, eventually falling to the ground and crushing an opponent. This attack can be countered with a hammer.
Gnarantulas can be fought alongside Pidgits. If there are four Gnaratulas with no other enemies in battle, all the Gnaratulas to the right are green and all the Gnaratulas on the left are red.
Gnarantulas seem to reference Lakitus and Spinies, with each of its three forms resembling the latter or the former in some way (red Gnarantulas resemble cloud-less Lakitus with the colours of Spinies, green ones resemble Spinies with the colours of Lakitus, and the clouds they have look like the clouds on which Lakitus are often seen).
Names in other languages