This recipe is way simpler than I thought it would be and tastes just like it does at Arby's.  Enjoy.
Ingredients

• 1 cup mayonnaise 
• 3 tablespoon bottled horseradish cream sauce
• 1 tablespoon sugar

Directions

1. Mix all well. Keep refrigerated, tightly covered to use in 2 weeks. Do not freeze.  
2. Enjoy on everything!