It is announcer addon.
It warns you raid or paty about:
1)Gain and fade of Shield Wall, Last Stand (warrior/druid/dk versions).
2)Disarm/Ripost/Dismantle on you.
3)Taunt-like as well as Mass-taunt miss|resist|immune, of any class.
Announce Shield Bash use and interrupt.
Announce party/raid member and pets taunt uses.
You can turn announce of sh.bash and taunt on and off.