There is a picking technique that when executed correctly will produce a harmonic. This harmonic will make the note sound much higher and sometimes blends with the original fretted note. The resulting note will sound like it's screaming out of your guitar. It adds a lot of excitement to your solos when placed tastefully, or even not so tastefully. Anyway, the technique can be done in many ways.
Some people like to choke up on the pick to get their thumb close to the strings.
They touch the string with part of the tip of the thumb. Personally, I have found an easier way to achieve the same results. I use the side of my thumb instead of the tip. I actually rub the string with the part of my thumb that's behind the pick. The pick touches the string and after the pick has passed the string, my thumb gets in there to create the harmonic.