The Hydraphant is one of the largest Tyranid bio constructs seen on the battlefield. Its Ripper Tentacles can pull apart enemy titans with ease, and it has an array of secondary weaponry with which to decimate units of all types up close and at range.
Tyranid Harridans are huge nightmare creatures that fly above the battlefield, swooping to strike with Bio-Cannon and Crushing Claws. They can also carry Gargoyles, delivering them straight into the heart of the enemy.
The Termite is a tunnelling machine used to transport troops into battle. The premise is similar to deployment via spaceship drop, and the enemy player does not know exactly when, or where the Termite will appear.
Devastator Marines carry shoulder mounted missile launchers capable of destroying infantry and vehicles alike. A popular method of deploying them is via Thunderhawk Gunship, with a Dreadnought to provide cover and extra firepower.