Flood root

Roots,also referred to as Tentacles, are biological "structures" used by the Flood for defending their hives. They attack by whipping threats to the hive with great force, easily killing infantry and heavily damaging vehicles. They are also capable of grabbing lifeforms and converting them into Flood biomass. Flood roots were encountered during a battle on a Flood-controlled Shield World in February 2531, and during the Banished occupation of Installation 00 in 2559.

Halo Wars
Roots can be found as defensive structures similar to Base turrets, protecting colonies. They attack by whipping enemies. Despite being similar to buildings and not moving, they are technically units as they have a Y ability which converts units to flood spores.

Halo Wars 2
Flood tentacles in Halo Wars 2 are offensive structures, capable of bursting out of the ground underneath their enemies' feet anywhere on the battlefield. As such, tentacles are capable of emerging and attacking friendly bases. In the mission Light the Fuse, tentacles are found protecting the ruptures that continue to let Flood loose over the course of the mission. Flood tentacles are noticeably more dangerous, with their whip attack now dealing high area-of-effect damage, similar to the attack of an Abomination. To counter this, the tentacle has a lengthy wind-up animation, and a HUD element alerts the player where the tentacle is about to strike as to give them a chance to remove their units from the danger zone.

List of appearances

 * Halo Wars
 * Halo Wars 2