Toxicrene
The Toxicrene is a monstrous Tyranid designed as a more offense-minded Venomthrope. Spotting a dozen Lash Whips all filled to the brim with a hideously effective poison (namely 2+ poison, with Instant Death on a 6, ignoring armor because it's a Monstrous Creature) it is quite effective at dealing with tough enemies. Its model is very large: the massive tentacles make the Toxicrene nearly three times as wide and one and a half times as long, encouraging the use of pinning to be able to remove the tentacles while in transport.
On the tabletop the Toxicrene is an odd beast. While its hits are almost sure to wound, hitting is a bit of a problem with its low WS of 3, making it unlikely for you to wipe out a squad of Terminators in one round. It also possesses an odd shooting attack (alongside Toxic Miasma) in the form of a 12" S3 AP- Poisoned 2+ Large Blast, with the added bonus of having Armourbane on damaged or open-topped vehicles. The downside is that while Armorbane is useful, at the end of the day 3+2D6 is only an average of 10, with the 14 needed to even TOUCH the likes of a Land Raider being only a 1 in 12 chance. As such this shooting attack is best not relied upon. At least it doesn't suffer from the creature's average BS like with its brother, the Maleceptor. Let Carnifexes take care of the vehicles if you must.
According to GW's advertising, the Toxicrene is effective at fighting and stalling powerful Monstrous Creatures like Riptides. None of the Tau players are taking this seriously, a scoffing not entirely undeserved when you consider the Toxicrene is footslogging while Riptides are faster with jet packs and easy ways to ignore cover. That said, if it DOES get in contact with an enemy Monstrous Creature it is going to hurt, making this a DISTRACTION CARNIFEX at worst. In direct combat however it is good at whittling down Terminator squads, especially those running with Apothecaries/Sanguinary Guard.