The crinoline is a hoop skirt that women in the 19th century wore under their actual skirts. It was made from horsehair and thread or steel, and the whole purpose of the huge apparatus was to make the skirt look more... skirt-like.
Also, since you were basically wearing a cage around your legs, you could probably use the crinoline to trap small animals and kick them to death.
How It Could Kill You:
The steel crinoline was actually so deadly it's amazing this thing was ever worn at all. Because of its design, it was quite susceptible to gusts of wind. There are tales of women on piers that were swept up and carried out to sea, where they promptly drowned due to having a fucking steel cage tied to their waists. It was also a bad idea to hang around cliffs or tall buildings in this sort of contraption.
The skirts would get entangled in the spokes of carriages, presumably dragging the women screaming down the street. Then there was the less obvious dangers, such as knocking over candles. Don't laugh; the poet Henry Wadsworth Longfellow's second wife went up in flames this way, and she wasn't the only one.
Wait, it gets worse. In 1863 in Santiago, Chile, between 2000 and 3000 people died in a church fire. When a gas lamp lit the veils on the walls, people tried to run outside, but the width of the women's skirts blocked the door, and crinolines with women inside piled up in front of the exit, making an escape impossible even for the people who'd been smart enough not to wear hoop skirts.
What the Fuck Were They Thinking?
The crinoline, in making someone's ass look big, would also make their waist look smaller, and so women didn't have to wear a corset. Why would they take such extravagant measures to avoid that? Well...
The corset, if you're one of the small percentage of our readership not wearing one right now, was meant to suck in a woman's problem-areas with the small side effect of cutting off all circulation between their legs and head.
The result was not so much an hourglass figure, but a body that became an actual hourglass. Queen Maud of Norway was famous for her very small waistline, and many of her gowns are still exhibited so everyone can view their beauty and not-at-all freakishness.
Compressing her organs as only a queen can.
How It Could Kill You:
The act of donning a corset didn't actually become truly dangerous until people started tight lacing them to the point that their insides were squeezed like a toothpaste tube.
Unsurprisingly, when tight lacing was fashionable people didn't breathe very well. With their liver in their throats and their lungs in their bellies, Victorian women invented "the heaving bosoms." Breathing the wrong way in one of these things could break a rib (a serious injury in the days before anesthesia) and cramming all of the organs inwards could cause internal bleeding. Female impersonator, Joseph Hennella, was doubly unfortunate when, in 1912, he first collapsed on stage as the result of the tight lacing from his corset, and then when The New York Times wrote the part about what killed him, they said it was his "increasing girth."