Sporocyst

Bloated for combat.

Pretty much a immobile version of the Tyrannocyte that is launched with an even more powerful muscle spasms from the Hive Ships in order to bury and root itself into the ground like Ticks do into flesh. When burrowed, they release bacteria that pollute the atmosphere (the same way as Spore Chimneys do), and when threatened, it will roll out its five Deathspitters and vomit out Spore Mines or, in the case of Flyers, a Mucolid Spore. Added that the darn thing is a psychic resonator that strengthens the overall capabilities of Nids around it.

Short: It's both planetary digestion unit, strongpoint and psychic relay for the Tyranids. All put in one package.

Tyrannic Bio-Organisms
Leader Organisms:	Broodlord - Hive Tyrant - Neurotyrant - Norn Queen - Tyranid Warrior
Small Creatures:	Barbgaunt - Gargoyle - Genestealer - Hormagaunt Neurogaunt - Ripper - Spinegaunt - Termagant
Medium Size Creatures:	Biovore - Hive Guard - Lictor - Neurothrope - Parasite of Mortrex - Pyrovore Ravener - Tyrant Guard - Venomthrope - Von Ryan's Leaper - Zoanthrope
Monstrous Creatures:	Carnifex (Screamer-Killer - Stone Crusher - Thornback) - Dimachaeron Exocrine - Haruspex - Malanthrope - Maleceptor - Mawloc Psychophage - Tervigon - Toxicrene - Trygon - Tyrannofex
Gargantuan Creatures:	Cerebore - Dactylis - Hierodule - Malefactor - Nautiloid - Viragon
Flying Creatures:	Harpy - Harridan - Hive Crone - Mucolid Spore
Bio-Titans:	Dominatrix - Hierophant - Hydraphant - Viciator
Floral Structures:	Capillary Tower - Reclamation Pool
Spaceborne Creatures:	Ether-Swimming Brood - Mycetic Spore - Tyrannocyte
Other Organisms:	Bio-Weapons - Cortex Leech - Meiotic Spore - Neurocyte Neuroloid - Spore Mine - Sporocyst - Zoats
Unique Creatures:	Deathleaper - Laius Horror - Old One-Eye - The Red Terror - Swarmlord
Auxiliaries:	Genestealer Cult