When magic, the powers of the Gods and immortals, or the insanity of reality warping rear their ugly head, the cosmos may have a hard time keeping these in check in line with the laws of reality. Especially atrocious breaches are answered by the most direct show of force imaginable for the universe itself; Paradox Crystals.
These deep purple crystals grow on the offending objects or beings and stop their breaching of reality. The crystals only do just enough to contain and protect the world from the dangerous and reality-bending paradoxs they contain. The crystals are known to be nearly unbreakable; but anyone who does break them is either effected by the paradox and similarly trapped or has a powerful backlash depending on the paradox. It is not known if a paradox can be freed once contained by the crystals; it seems the easiest course of action is to just coat the area in crystal growth and leave it. For this reason; deep dungeons and shrines may hide these scenes of contained reality bending.
 Unstoppable Force, Immovable Object
Two warriors, Saposa the Brave and Irreas the Stout, are frozen in time by purple crystals. Saposa once wielded the unstoppable spear of power, and Irreas carried the unbreakable, immobile shield of the mountain. The moment these two decided to fight sealed their fates; Saposa stuck in a pose of ferocity, charging down at Irreas as he holds up his shield to defend. The moment the two things were placed in a collision course was the moment they were trapped in crystal.
Technically; Saposa's spear has not stopped moving. It is still moving, just with space arbitrarily extending between the two figures without them moving, a tiny sock of space-warp infinitely extending between the two figures, invisible to the naked eye. For this reason these are among the most dangerous of all paradoxes- anyone who chips a paradox crystal is struck with a mere fraction of the nigh-infinite distance the spear has traveled since containment; a single line bisects your body and explodes outwards like a tube. This deals a fraction of 1d∞ damage, causing death.
 Squared Circle
This paradox is a drawn picture of a squared circle; a perfect geometric abomination. The crystals have grown over the image in a cross shape, thus blocking anyone from viewing more then a single corner at a time. Whenever you look at a corner, it either looks like a point or a curve, with no in between, but the geometry of this picture is apparent if beheld in its full form.
If the crystals are chipped or broken; the paradox's energy slips lose. The offender is struck by a bolt of mathemagical light that breaks and bends their entire body into a geometric shape; a cube, pyramid, sphere, or prism. Needless to say, this is fatal and very gory.
 Chicken or the Egg
This crystal-growth is unique. Instead of a solid block, it is more organized as a small “pen” around a single chicken. The chicken will always take a few steps, lay an egg, then rapidly age and die while a chick comes out of the egg and grows to adulthood, laying its own egg, and repeating the process. Truthfully, the process of this is going at normal speed, where as when the spell was original cast that created this paradox had them going backwards at an intensely face rate to see the truth of what came first. As a paradox, the true answer was not discovered.
Also; anyone looking closely at the chicken will notice it has a sharp large dinosaur claw on its foot and small teeth in its beak; it is prehistoric. This is because the current iteration of the chicken is slowly working its way back up to modern day evolved chickens. Anyone who steps foot in the pen or tries to eat the chicken will get blasted by the paradox crystals and either turn into a neanderthal caveman or rapidly age 1d40 years and probably die.
 Married Bachelor
After an unfortunate attempt to end the literal soul-binding marriage rites of their foreign culture with magical divorce; this bachelor is still married. He is still alive, just with crystal growths on his mouth, hands, and genitals. When he tried to speak his false vows, his mouth crystallized. When he tried to sign away, his hands froze. Any attempt for him to marry again causes localized Earthquakes and mutations in his potential bride that transforms them into animals or something else illegible for marriage. He's given up and has returned to his first wife, and happily supports his family by shaving off small, safe amounts of dust from his paradox crystals and selling them to local philosophers and deep thinkers, who use them to help suss out the mysteries of the universe.
 Falling-Tree Crescendo
This tree was about to fall in a forest with sound, just without anyone to hear it. It has such been frozen in place, half fallen, held aloft by purple crystal growths. Those who chip or damage the crystals will take 1d6 damage from a split second of a very loud crashing noise. The tree also has a small cult of paradox watchers nearby who sit around it all day in their camp; they believe if enough people gather to this place the tree will be unstuck in time and fall, allowing everyone to bask in the glory of its paradox sound.
 Time Paradoxes
This isn't a single incident; instead these are pretty common and the largest sources of purple paradox crystals. However, as with all of the paradox crystals, they are very dangerous to try and gather. Time Paradoxes always surround foolish Sorcerers who try to influence the past and freeze around pairs of people who meet their past selves. Once the older half of them dies from old age the younger one will be freed with their memory continued at the point right before they noticed their older self. Because of this, occasionally people age up several years in a single second with several years gone past since their last memory. As such, it's highly recommended to only go into the past once you're very old so you die quick and it's less likely for your younger self to recognize you; that's why all the cryptic messages people get from the future are from insane senile old people who look familiar!
Additionally; any character who attempts to harvest Paradox Crystal disappears and reappears in the same place 2d6 hours in the future from a time warp. If either die land on a 6 then instead they are gone for 1d20x2 years. If the die lands on a 20 then instead they return for 1d100 eons.
 The Bronze Ship
This ship is frozen on a small island made of paradox crystal, with about half the crew below decks also frozen, with the rest of them on deck having long since died and become decaying skeletons. Belonging to an advanced ancient civilization; this ship left port with a full set of mechanical supplies and had stopped near this sandbar to make repairs. The oracle crafted a helpful prophecy to ensure that the same ship would return to port. It seems that at some point the ship was not the same ship that left, as all its parts were replaced, but done over a long enough time that a paradox occurred. Those who interact with these crystals have a chance to take 2d6 damage from their body parts splitting and multiplying and decaying in rapid and painful accelerated healing.
 The Liars Tongue
This is a cut out tongue on a special metal alter of truth-metal. The pale white metal prevents anything from lying that is touching it. The tongue of a master spy was cut from his mouth and placed on an alter to speak the truth. The tongue retained some of the cleverness of its master and declared that “This statement is false!” causing the tongue to solidify into paradox crystal instead. This crystal releases a dark cloud of vapor when disturbed which causes things to lose description while within the fog. You cannot tell beings or objects apart, everything merely has a similar vague shape and movement. This is a very small and special collection of paradox crystal, and the few who have gathered some become lost to history over time as a special secondary effect of gathering this crystal multiple times; fading into wraiths that lose both physical substance and others lose the memory of the subject in their mind.