At first you might believe it's a riff on the pina colada. Yet behind the breezy pineapple and coconut, there's a creamy vanilla, a tingle of spice and more elusive tropical memories.

"There's a lot going on," said Jennifer Pratt of the frozen drink dubbed “Spongebob.”

It's part of a changing lineup of summertime slushies served at Pratt's on Monroe in downtown Mexico. On the menu over the past week were two that need little explanation -- berry margarita and orange dreamsicle -- and a couple that defy the imagination.

Spongebob is a blend of pineapple juice and four different rums. Malibu accounts for the kinship with pina colada. Others contribute vanilla and spice, although it's difficult to pin down a precise recipe.

"We just start creating until it tastes good," Pratt explained.

That's how they came up with Feeling Froggy, a glaringly green concoction with a surprisingly bright glaze. Tart and juicy kiwi paired with strawberry juice provides a balance of exotic and common fruits that prances over an herbaceous foundation.

It's nothing more than a combination of Malibu and a traditional light rum, along with the fruit juices. Again, however, it offers the palate something to contemplate.

And it's fun -- as is the dreamsicle, which is a memory of childhood through an alcoholic haze.

In the role of vanilla ice cream is a cake flavored vodka and it plays well. Orange is in the forefront, but the essence of creamy richness is always present.

Blender drinks first gained notice when Americans tourists escaping Prohibition encountered frozen daiquiris in Cuban bars like El Floridita. Thanks to pina coladas and tiki drinks, they took off in the 1950s.

By the early '70s frozen cocktails were on such a high that Dallas restaurateur Mariano Martinez tinkered with an ice cream maker and other parts to create the first frozen margarita machine, which now resides at the Smithsonian.

Unfortunately, the corporate world caught on and pre-made mixes took over the market. The quality -- and reputation -- of the blender drink went into a nosedive.

Comparing pre-made versus from scratch, Pratt notes that "It's just not the same."

With the rise of "mixologists" and their willingness to explore came the revival of the frozen cocktail. Bartenders returned to hand squeezed juices, fresh ingredients and quality spirits to produce cooling concoctions for discerning sorts.

Pratt's is not so snooty. They work from scratch, but with good canned juices -- the same vibe, the same creative spirit at a more reasonable cost.