There are no achievements in Classic.
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Nausea, Heartburn, Indigestion... (25 player) - Live
Nausea, Heartburn, Indigestion... (25 player) - PTR
Nausea, Heartburn, Indigestion... (25 player) - PTR 2
Nausea, Heartburn, Indigestion... (25 player) - Beta
Nausea, Heartburn, Indigestion... (25 player) - Wrath of the Lich King
Nausea, Heartburn, Indigestion... (25 player) - Cataclysm