Liquid body: 2 of these monsters can combine to become 1 size larger than it, double its CR, it’s str and add the HP of the 2 zuwytox it can do this up to a huge size and can separate down to a small size dividing the CR, str and HP by 2

Slam: unarmed melee attack +5 to hit, range 5ft, target 1, hit 8 (2d6) cold damage

For every size above small times all the numbers in the attack by 4 and divide by 3 (round up) repeat this 

e.g - 4 small zuwytox merge to a large so you times by 8 and divide by 6

Disperse: on a DC 18 dex save from a non magical weapon attack the attack misses and it goes straight through the creature to maybe hit one behind