They had them in march but you had to ask (MDR). They had them in december all over the MDR and they were pushing you to buy them. Not sure if they are on the way out or if they just scaled down the push.
They offered them on our recent cruises during the Pirate Night MDR (March & April 2016). The cost was $7.99 and it came with a "smoothie" but I think it was more like a milkshake They also sold the cups with the clip on lights during the Pirate Night deck party, I'm not sure of the cost because we did not purchase one.
The mug was offered at the beginning of our Pirate Night meal. Ours was $7 which included a fill of your choice of smoothie. We thought it was totally worth it (and they washed the glass for you at the end of the meal!). This was on the Dream in March.
We just got one last week. My son enjoyed the smoothie. However, our servers didn't wash ours as someone else stated above. But, no biggie. I always bring a small bottle of dishwashing liquid to wash items in the room so we were able to wash it if we wanted.
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