Spaghettification is the process by which any object would be stretched and ripped apart by gravitational forces on falling into a black hole. Essentially, when a particle draws too close to the source of the powerful gravitational field, it is stretched into long thin shapes, like pasta.
The term was coined by Stephen Hawking in his book, A Brief History of Time, where he likened this process to spaghetti. Much like other aspects of the black hole theory and model, this effect of drawing too close to a black hole remains untested, unobserved and unproven, and relates to areas of physics that remain largely unexplored, namely the concept of a force so powerful that no matter what components make up a piece of matter, it will be stretched further than is deemed by many to be within the realms of physical plausibility.
“Sure, black holes can kill us, and in a variety of interesting and gruesome ways. But, all in all, we may owe our very existence to them.” ― Phil Plait