All images: NASA, JSTOR, Wikimedia
To put it in simple words, spaghettification (also known as noodle effect) is the vertical and horizontal compression of objects into long thin shapes in a very strong, non-homogeneous gravitational field. This phenomenon is caused by extreme tidal forces.
Black holes are among the most mysterious cosmic objects, much studied but not fully understood yet. The gravitational pull in these objects is so strong that nothing, not even light, can escape it. Spaghettification occurs when an object falls into a black hole and experiences varying gravitational pulls at its ends.
Now this scenario is hypothetical, as the nearest black hole to our solar system is 1,500 light-years away, reaching it is impossible. But if you were to fall into a black hole, you would experience compression horizontally and elongation vertically.
Smaller Black Holes cause more severe spaghettification compared to supermassive black holes. This is because a smaller black hole has stronger tidal forces near the event horizon.