A youth launches Twitter social media application on a tablet in Cairo, Egypt, January 24, 2016. Reuters Twitter is facing serious issues and now one Wall Street analyst has turned on it in a big way.

Scott Devitt at Stifel released a note Monday downgrading Twitter from a "Hold" to a "Sell" rating and in doing so eviscerated the company.

Devitt compared Twitter to tech fads that have imploded before, writing: "We are returning our rating on Twitter shares back to where it should have been all along — Sell."

Devitt added, "Twitter is a product that has never fully developed into a sustainable public company due to either poor strategy, poor execution, or that it was never destined to be one."

Devitt noted that Twitter has 320 million monthly active users (MAU), one of the most important metrics for a social media platform.

However compared to other tech companies this is a paltry number.

For instance Yahoo has more than 1 billion MAUs and has a much lower valuation. AOL had around 200 million MAUs before being sold to Verizon. Devitt also invoked tech busts Groupon and Zynga as comparisons to Twitter. Both stocks trade under $3 per share.

"Groupon and Zynga were notable Internet companies that quickly rose to prominence followed by a rapid decline in their share prices," he wrote. "Although these companies are not at Twitter's scale, both still have ~50mm 'users' and once had many more."

Devitt fears that based on recent trends, Twitter's MAUs may even start to decline.

Now, Devitt has always been down on Twitter, but in recent months he had become more bullish.

Citing co-founder Jack Dorsey's return as CEO, he believed that Twitter could develop new products to invigorate engagement with the platform. According to this most recent note, those hopes are gone.

"We took a respite from the negativity for a brief period in the past three months based on the belief that if the product strategy were going to show signs of improvement we might see the stock respond," he wrote.

"Well the stock sure responded (negatively!) and the product still resembles its former self while the individual in charge of the product as recently as two weeks ago now resides at Instagram."

Devitt's final comparison highlighted the divergent fortunes of Twitter and Facebook.

The two companies, once thought to be rivals, have gone on totally different paths. Whereas Facebook is reporting over 1 billion users and revenues taking off, Twitter is struggling mightily.

Two charts in Devitt's note highlights just how far ahead Facebook has pulled.

One the one hand, Facebook has begun to crush Twitter in time spent on the platform.

Which in turn translates to higher revenue, as more users click on ads allowing Facebook to monetize.

All of these trends lead Devitt to believe that not only has Twitter failed to live up to the hopes it had just a few years ago, but also has a long way to fall.

Devitt's new target price is $14.00 per share. Twitter closed trading on Monday at $17.90.