Limacina erecta

The grub plant possesses unusual sensory cells at the tips of slender projections that emerge from the top of each stem. These not only resemble the tentacles of true slugs but also have a primitive sense of smell and respond to volatile chemicals emitted by animals that approach it. This allows the grub plant to retract to a smaller size as a defense against being eaten. These unusual cells place the grub plant in the class of zooplante found on Pandora that have characteristics of both plant and animal. 

Due to the high concentration of lipids produced in the grub plant, they are a favored food of animals, but inedible to the Na'vi. The humans on Pandora are experimenting with it for use as a cheap biofuel.