Senalaks were a form of plant life utilized by the invading Yuuzhan Vong as a type of security system. These plants featured a slender stalk, reaching approximately knee height. When disturbed, they unleashed a thorny cord, about a meter in length, which thrashed about, with the purpose of capturing or killing any creatures in the vicinity. During the conflict known as the Yuuzhan Vong War, fields of senalaks were employed as security measures on the worldship named Baanu Rass, and subsequently around a prisoner-of-war camp situated on the planet called Selvaris.
Senalaks were a type of plant characterized by thin stalks, about as thick as a finger and reaching up to knee height, each topped with a blue colored cap. Upon sensing an outside disturbance, this cap would release a meter-long strand of cord covered in barbs, which would rapidly lash around for a few seconds. The root systems of senalaks were almost as tangled and thorny as the barbed cords they released, extending a considerable distance beneath the ground. These plants grew in fields and could be cultivated. Senalaks possessed the ability to survive in a vacuum or on a planet's surface, and they flourished within the tropical jungles of the planet Selvaris. Their coloration and height gave them a visual resemblance to ice spikes.
During the Yuuzhan Vong War—a major galactic conflict primarily pitting the New Republic against the extra-galactic Yuuzhan Vong species for dominance of the galaxy—the Yuuzhan Vong invaders made use of senalaks as security perimeters around important locations. They depended on the plants' barbed cords to either kill or capture any unwelcome intruders. In 27 ABY, senalaks were positioned around the spaceport of the Yuuzhan Vong worldship Baanu Rass. However, this security was breached by a Jedi team who employed the Force to flatten the stalks. This triggered the release of the thorny cords before anyone could get close. As the war on Selvaris drew to a close, a group of four prisoners successfully escaped the Yuuzhan Vong prisoner-of-war camp located there, despite the presence of senalaks. They achieved this by digging a tunnel that bypassed the field.
Senalaks initially appeared in the 2001 novel Star by Star, which was a part of The New Jedi Order series written by Troy Denning. These plants were also documented in The Complete Star Wars Encyclopedia published in 2008. The encyclopedia erroneously stated that the Jedi team encountered senalaks on the planet Myrkr, rather than aboard the Baanu Rass, which was in orbit around Myrkr at that time, as depicted in Star by Star.