Simple weakaura that announces when certain spells are used in party chat.
If you're missing any spell, let me know.
It is also easy to add a spell, if you look at how the others are made under "Trigger" and "Conditions" tabs. Duplicate what you find there.
Current spells/auras being announced:
Sigil of Silence
Sigil of Misery
Sigil of Chains
Metamorphosis
Last Resort