Each creature is randomly generated using using p5js. There are 6 base colors. Rarity is determined based on the number of colors used. The most rare combination is when all 4 creatures share the same color. Roughly 1 in 216 mints should have Colors=1.

Probabilities:
Colors = 1 (.46%)
Colors = 2 (16.2%)
Colors = 3 (55.5%)
Colors = 4 (27.7%)