I had an onion on the counter; eggs, half a chicken breast, and cooked rice in my refrigerator. I got the brilliant brainwave to make oyakodon. Another brainwave, and I decided to mix the rice with a bit of rice vinegar and sugar, and to make the eggs, onion, and chicken into a flat omelette with some soba tsuyu stirred into it (I figured soba tsuyu has dashi, mirin, and soy sauce, so made a nice shortcut for normal oyakodon ingredients). From there, I cut up nori, layered a bit of the sushi rice into each rectangle, and then tucked in a strip of omelette.
Maybe it's a hybrid of oyakodon and sushi; maybe it's a sloppy, artless handroll. Maybe it's simply an abomination. However you want to explain this one, it made for a happy dinner.