He always appears on the race track less than a second after the 4th player joins the race, regardless if they are a player or a bot.

How often does the wampus show up?

The Wampus shows up on the track very rarely. He joins at the very last second, tagging along with the 5th racer, but he rewards everyone who beats him with $50,000!

How do you get the wampus car in Nitro type?

You currently can not get the Wampus Car for as it is an exclusive to him and him only. :P. Actually The Corndog said in the News that if you complete one million races you will get his car.