The Covenant Warrior Form is a formidable enemy; it is capable of a deadly physical attack using its tentacles (once the arms of the Covenant host), as well as having the ability to wield both human and Covenant weapons. It is very fast, very strong, and can jump great distances. Due to the Flood Controller's indifference to its host's discomfort, it is nearly immune to some weapons (notably the sniper rifle), but reliance on the host life support systems render it vulnerable to shotgun blasts. It does not have the capability of using Covenant Energy Shields, though it does, on occasion, use Active Camoflague Devices.
-- from halo.bungie.org
's "Anatomy of a Flood" section.
Specific Link: Covenant Warrior Form