The Hotcake, like other guitar pedals, is a small box that sits at the feet of the guitarist, and can be switched on and off while the musician is in full swing. It adds an effect to the sound of the guitar and makes that distorted, fuzzy sound (mimicking the sound of an overloaded amplifier, without risking damage to the amplifier) that has been at the heart of rock and roll forever.
The idea is to spend thousands of dollars amplifying the sound of a guitar perfectly and then ruin it. But ruin it just right. The effect produced depends on the electronics inside the box, and the Hotcake is globally renowned for its brilliant sound. In music-speak, most distortion effects provide distortion at the expensive of the clean, original character of the guitar.
The Hotcake retains the underlying quality of the guitar while provide a nice fat, thick distortion that guitarists go crazy over.