The NASA Crawler-Transporter
As the largest tracked vehicles in existence, it may not surprise you to know that they have over 5,000HP and it takes eleven people to drive one. You won’t be getting anywhere quickly on one of these, with a top speed of under 2km/h, and you definitely won’t be getting anywhere cheaply with it chewing through around 350L of diesel per km.
(Image credit; NASA, KSC)