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I really like your friend's the best so far. There's great motion in it, I can see the mushrooms growing first on the sheet, entering his nose, passing through his body to his toes. The end is a bit icky which makes it really funny. It's a winner.

Yes, he's a bit of a limerick genius! I think I got bamboozled by the big words on some of the other entries, but a limerick has to be simple and if they don't see that they are crazy themselves!