Heck is a verse with negative dimensions that is too small to be given an accurate measure of size or shape. It is always the smallest verse, as whenever a new verse is created that is smaller, it will shrink to a size smaller than that of the new verse's, even if it has to go below zero.
It's been theorized that something exists inside it, but Heck is too small to be observed by almost all realities. Even if something was able to see something of Heck's size, Heck would still be very difficult to observe because it moves fast enough to create rifts between verses, causing it to change which verse it's in at an extremely fast rate.
Some may think that This is the true smallest verse. Don't bother making a smaller verse, you can't. is the smallest verse, but this can easily be proven false, since it's categories say the Protoverse is smaller. However, the same applies to the Protoverse, as Heck's properties make the Protoverse the second smallest verse. This also applies to the Microcosm.
The Biggestverse's current description contradicts itself several times, invalidating it as a contender for the smallest verse. Even if it's description wasn't self-contradictory, Heck's properties would make it the second smallest verse anyway. Since the Numberblocksverse's description says it is larger than the Biggestverse, which is larger than Heck is, it's also impossible for it to be the smallest verse.
The recently created Hecc has extremely similar properties to Heck, yet Heck would still be smaller. This is because when one shrinks below the other, the other will shrink and assume the position of smallest Verse, and this will continue forever between the two verses. The difference in size between the two makes it so that growth speed does not have much of an effect, making Hecc's main edge over Heck almost useless. But the above is assuming the '2x property' isn't active, and that property would only worsen things for Hecc. Hecc's alleged property of always remaining 2x the size of Heck would backfire since Heck's size is not able to be measured in real numbers, but imaginary numbers are usable. The imaginary number used to measure Heck is one that would not use the imaginary unit "i" like most imaginary numbers, but use a different imaginary unit that allows the number to be smaller than zero and negative numbers, but still positive. That concept may sound completely impossible to most people that may be reading this, but it's called an imaginary number for a reason, therefore making it possible. A positive number cannot be greater than itself multiplied by two, therefore making Heck the smallest verse. Hecc has shown that it's '2x property' fluctuates from 0.5x to 2x from time to time, but Heck has properties that counter either case. 2x is countered by the Heck Number (rendering Heck the smallest), while 0.5x is countered by Heck's normal shrinking properties (rendering the position contested). Basically, the position for smallest Verse would either be kept by Heck or eternally contested between Hecc and Heck.
Verseuni and everything it contains is paradoxical and therefore not a contender for the smallest verse. Additionally, Verseuni's size may be negative, but the Heck Number is said to be smaller than negative numbers yet still positive.