Wild Mustang champagne cocktail
Looking online, I found this  menu from a Monk's Grill that appears to be in Vancouver. Under Champagne Cocktails it lists a Wild Mustand as having Skyy vodka and Grand Marnier. See below, copied from the menu:


  WILD MUSTANG splash of Skyy Vodka &amp; Grand Marnier


Searching on end, however, I have not been able to find a recipe for the drink. Based on some other recipes I've found that are similar, here's a suggestion you might start with:

In a martini glass,


Pour 1 oz. Grand Marnier
Add a splash of your favorite vodka
Fill the remainder of the glass with well-chilled champagne or sparkling wine
Garnish with a slice of orange


Hopefully this will get you started and, as with all mixed drinks, you can refine to your taste.