While doing "research" for our brutal Game of Burgers, we were offered an off-menu special at Umami in Costa Mesa that we couldn't refuse.
A patty from the sea; the Shrimp Pad Thai Burger: Grilled shrimp, bean sprout, carrot, green onion, cilantro, Thai basil and peanut-tamarind sauce. Up there at $15, but a worthy splurge, indeed.
A little Google action shows that it's also available at UMAMIcatessan, the Umami sister inside of the Orpheum in Los Angeles, but there's no reason for now to make the drive.
The sweet and tangy sauce accents so many assertive greens and veggies, and ground peanut adds a textural contrast, but so many flavors take nothing away from the shrimp patty, a 3/4-inch puck of whole wild shrimp stuck together with shrimp run through the food processor--it gives a new meaning to "shrimp paste."
The bartender said it would be around for a month or so, but wasn't really for sure. I'd say try it while you can.