GameTooltip:SetUnitAura shows the tooltip for a unit's aura.

 GameTooltip:SetUnitAura("unitId", auraIndex[, filter])

Arguments

("unitId",auraIndex[, filter])

unitId 

String - the unitId of the unit whose aura is to be shown

auraIndex 

Number - the index of the aura to be shown

filter 

same as UnitAura(...) "HARMFUL" for debuffs, "HELP" for buffs, "RAID" for raid specific, etc...

Returns

unknown