Tyrannofex
A Tyrannofex is a large type of Tyranid, somewhat similar to a Tervigon. It seems it was intended to be a big-ass creature which pounds its foe from afar (as in 48" max, which of course we know is the really long range) , using a variety (i.e. 3 types) of bio-weaponry.
According to the fluff, it smells pretty bad when scared, attracting Hormagaunts and other Tyranid organisms, which then proceed to dice and shred the enemy, with their fantastically anti-terminator weapons, who will invariably be smashing this brick of an animal in Close-Combat, as it has a 2+ Armour Save and a Strength, Toughness and Wounds value of 6, and costing 250 points. Of course, being a Dakka-fex of sorts, it has only 3 Attacks and Claws and Teeth to defend itself with, as well as the aforementioned non-existent pheromone trail.