First strike
Menace (This creature can't be blocked except by two or more creatures.)
{T}, Sacrifice Goldhound: Add one mana of any color.
Even when it is on a creature, Treasure is an artifact type and not a creature type. Similarly, Dog is always a creature type and not an artifact type.
If an effect refers to a Treasure, it means any Treasure artifact, not just a Treasure artifact token.
Since Goldhound is a creature, its {T} ability can't be activated the turn that it enters the battlefield or the turn a player gains control of it unless it has haste.