Quicksilver slimes are among the rarest slimes on the Far, Far Range, thanks in large part to their only known habitat being owned exclusively by Mochi Miles. Quicksilver slimes are lightning quick, and feed on electricity. This is generally accomplished by their moving really fast and slowly accumulating the static charge they generate. However, Mochi has decided to speed up the process and created a method for feeding them energy in a far more direct fashion.
Quicksilver slimes are not normally harmful to a rancher as the static they generate has a low current. However, Mochi's method of feeding them a great deal of electricity at once makes quicksilver slimes overcharged with a current high enough to be harmful if touched. So be careful when firing those spark shots as a mob of well-fed quicksilvers could leave you zapped!
Mochi sells quicksilver plorts off-market and little is known about her buyers or their motives.