-- Lavender Brown, upon first seeing a Skrewt (GF13)
"I can certainly see why we're trying to keep them alive. Who wouldn't want pets that can burn, sting, and bite all at once?"
-- Draco Malfoy (GF13)
The Blast-Ended Skrewt is a stange hybrid creature bred by Hagrid at Hogwarts in the fall of 1994, by crossing manticores and fire-crabs.
Newly-hatched skrewts looked like pale, slimy, deformed, shell-less lobsters. They had no heads but had legs sticking out at odd angles. The creatures were about six inches long and smelled strongly of rotten fish. Sparks flew out from their ends every so often which propelled them forward a few inches. Some skrewts had stings--Hagrid suspected that these were the males--and the females had suckers on their bellies to suck blood. Hagrid has the students try to see what they will eat (GF13).
After two months, the skrewts were about three feet long and extremely ill-tempered. When kept together, they attacked and killed each other, so Hagrid tried keeping them in separate crates (GF16). They developed gray, shiny armor and began to look like a cross between giant scorpions and elongated crabs. They still expelled fire from one end, although since they had no heads it was difficult to determine which end that was. This blast of flame shot the skrewt in the opposite direction several yards. Hagrid thinks the skrewts need exercise, and has his students try taking them for a walk (GF18).
By December, the skrewts were six feet long. They held their stings arched over their backs and were extremely dangerous and repulsive. Hagrid tries to see if they might hibernate, with teddy bears (GF21).
By June, they were ten feet long and had become incredibly dangerous, fearsome creatures. They looked like a gigantic scorpions with stings curled over their backs. Their armor reflected magic spells and it used its fiery blast to hurl itself at its foe. It's single undefended spot is its fleshy, armor-less underside. Hagrid placed a full-grown skrewt in the maze for the third task of the Triwizard Tournament. Harry defeated it with a luckily-aimed Impediment Curse in its belly (GF31).
Hagrid started in September with several hundred skrewts. By the following June, there were almost none left -- all we know of is the one that was in the maze. This isn't surprising since they have no mouths and apparently don't eat, added to the fact that they pretty much killed each other off. All in all, it would seem that Hagrid's experiment in breeding magical creatures wasn't much of a success.
- We might guess that the final remaining specimen, once it recovered from the curse, was released into the forbidden forest, where all wild things are released in the end (BP-Blue Peter Show).