General Mess:
* As messy as a toddler's art project.
* As messy as a hurricane's aftermath.
* As messy as a cat's breakfast.
* As messy as a dog's bed after a long day.
* As messy as a child's playroom.
Specific Types of Mess:
* As tangled as a bird's nest. (For hair or cords)
* As spilled as a paint can. (For spills)
* As cluttered as a junk drawer. (For disorganized spaces)
* As smeared as lipstick on a napkin. (For stains)
* As scattered as confetti after a parade. (For scattered items)
You can also choose a simile based on the degree of messiness:
* As messy as a light dusting of flour. (For a small mess)
* As messy as a garbage dump. (For a huge mess)
Remember to choose the simile that best fits the specific context and level of messiness you want to describe.