Invading Felguard

From WoWWiki

Invading Felguards are huge level 60 felguards that spawn from Dark Portal in the Blasted Lands during the Dark Portal Opens event. They are the backbone of the demonic invasion and usually spawn in large numbers. Even so, they are the easiest to defeat of all the demons spewing out of the Dark Portal. They don't seem to drop any loot and despawn after they are killed.

Killing 10 Invading Felguards is the objective of  [60] Into the Breach, the reward is the Tabard of the Protector which looks identical to the Tabard of the Argent Dawn but has a purely cosmetic ability which does nothing but the graphic looks like Holy Nova and has a 5 minute cooldown.