The elaborate drinks are part of Starbucks' annual US Frappuccino Happy Hour promotion, which begins Friday and runs through May 14.
"We have got singular focus on Happy Hour this year," Kevin Johnson, the company's newly-anointed chief executive, said in a call with investors last week.
"We're going to bring at least one entirely new drink into Happy Hour this year that is going to be as good as Unicorn or better."
"Just stay tuned because we have a lot more coming," added Howard Schultz, the company's former chief executive. He credited the unicorn drink for driving "significant traffic, awareness [and] brand affinity" to the chain, which in recent quarters has struggled with disappointing sales.
Shares of Starbucks tumbled 4 per cent last week after the company posted disappointing same-store sales for the second quarter in the a row. (In 2016, the company's stock fell 7.5 per cent for similar reasons.)
We were inspired by thoughts of dark starry nights, looking up at the sky with a cool summer breeze.
The chain has tried -- and often failed -- to beef up sales by adding novelty items to its menus. Earlier this year, the company said it would stop selling beer and wine, as well as small-plates like truffle mac and cheese and bacon-wrapped figs at its stores. Those additions, rolled out with much fanfare a few years ago, had failed to resonate with customers.
But, company executives said, they had high hopes for their new Midnight Mocha drink. "People are gravitating toward vibrant colors," said Ryan Coombes, Starbucks' beverage development manager, no doubt referring to the popularity of the Unicorn Frappuccino.
But, he added: "Jet black is filling the void in unexpected places."