Mastigoproctus giganteus, the giant whip scorpion, also called the giant vinegaroon or grampus, is a species of whip scorpions in the family Thelyphonidae.
This species can grow to be 40-60 mm long, excluding the tail. They have six legs used for movement, two long antenniform front legs that they use to feel around for prey and detect vibrations, and two large pedipalps modified into claws that they use to crush their prey. They have a long, thin, whip-like tail, the origin of the common name whipscorpion. From the base of this tail they can spray a substance composed of 85% acetic acid in order to defend themselves. Acetic acid is the main component of vinegar, so the spray smells strongly of vinegar, leading to the common name "vinegaroon". Mastigoproctus giganteus have eight eyes: two in a pair on the front of the head and three on each side of the head. These eyes are very weak, so Mastigoproctus giganteus navigates mostly by feeling with its long front legs, tail, and pedipalps.
The Mastigoproctus giganteus is regarded as beneficial to agriculture and human residences by controlling insect populations.
This species is sold in the exotic animal trade as pets. They can be kept in terrariums, fed insects especially crickets, and handled with care.