The Lanlin was a vine-like creature which feasted on grief. It was unable to take people against their will, and so enticed victims to grab hold of it by morphing into their deceased loved ones.
Aiming to feast on Tanya Adeola's grief, the great trunk of the Lankin tried to lure her in using the image of her father. Other branches took the forms of Rachel and Orla'ath, with the aims of feasting upon Ram Singh and Miss Quill, respectively.
Miss Quill compared it to a chameleon, because of the way it camouflaged itself and snatched its prey. (TV: Nightvisiting)
Behind the scenes
The Lanlin shares similarities with the character Yivo from the Futurama film, The Beast with a Billion Backs. Both are unique beings with a seemingly infinite number of tentacles which can be seen sticking into peoples backs. Stylistically, it presented itself in the episode similarly to The First in the Buffy episode "Conversations with Dead People".
In technological terms, "LAN" is short for local-area network, while the definition of "Kin" is one's family or relations. Together, the name "Lankin" defines as "a local network of relations".