Tricos are a race of griffin-like creatures that appear in the Team Ico game The Last Guardian. These huge beasts have a composite biology, possessing traits from birds, cats and dogs. Unlike the deuteragonist Trico who accompanies the Boy throughout the game, all other Tricos in the game are under the control of the Master of the Valley.
The Tricos that serve the Master of the Valley are all adorned with mystical armour plating. This armour provides protection and allows the Master to control them, sending them out to abduct children from villages beyond the Nest so that they can be converted into energy that sustains the Master. Tricos are regarded with fear and hatred by humans because of this.
During the game, the Boy and Trico encounter an armoured Trico several times, noticing that it is watching them. Later on, it becomes clear that the armoured Tricos are hostile as they purposefully impede the Boy's progress and attack directly.
Towards the end of the game, when the Boy and Trico arrive at the Citadel, the Master summons a large group of its own enthralled Tricos to protect it. Trico is attacked by its armoured brethren and overwhelmed, being badly wounded and having the end of its tail severed. However, the severed tail falls into the Master's sanctum and still reacts to the light of the mystic mirror the Boy carries. When the Boy shines the mirror's light upon the Master, the severed tail fires a magical blast of electricity, destroying the Master. With the Master no longer controlling them, the armoured Tricos become disoriented, falling out of the sky in mid-flight.
It is safe to assume that without the Master's control, the Tricos eventually revert to their normal patterns of behaviour before their enthrallment (presumably their behaviour is similar to that of Trico). In a post-credits scene, it is revealed that the Trico that the Boy once journeyed with has found a mate and sired a young Trico.
The armoured Tricos appear to possess all the same abilities and attributes as the Boy's companion Trico; they possess great size and strength, they can recover quickly from serious injury and can fly. The one ability that the armoured Tricos don't seem to share with the Boy's Trico is the power to fire lightning from their tails. Most likely this power has been suppressed by the Master of the Valley through the armour they wear.