Biovore
The Biovore is a Tyranid living artillery. Games Workshop seems to have designed it with the goal of scarring the minds of the 40k fanbase and Neckbeards alike with pseudo-sexual xenos references, as the Biovore model both makes people uncomfortable and generates endless amounts of derp.
With a huge living cannon mounted on their backs, they grow spore mines deep inside themselves and then launch them through a powerful muscle spasm from their mind through their cannon at the enemy. The truth: Biovores reach orgasm in order to fire weird looking spore-seeds from their massive penis guns to assault the enemy, and just to put the icing on the cake these spores explode when reaching the enemy showering them in various nasty liquids. Damn it GW, stop letting Slaanesh write bad xenos slash fiction!
(In all honesty it's closer to a spitting cobra or a front-facing skunk than anything humans recognize as sexual. But that's not funny, so...)
It is no wonder the models look so derpy all the time. Looking utterly clueless and slow it is a wonder if the 'vores could do much in combat if attacked. The fact they are rumoured to have been created using Ork might go a way to explain that; putting two brainless species together is never a smart move...
A new model is out, and not as derpy. although it does have a ballsack on it's gun so it's really a wash.
On the Tabletop
Biovores are one of the few choices most Tyranid players are actually happy about. They're an artillery unit that can actually do its job, putting down large blasts from across the table at a halfway decent strength.