[Drew68]

It’s a fortified beverage, not beer by definition. Yeast dies above a 14% alcohol concentration so they are adding alcohol to make it 28%.

From the Samuel Adams website:

"The brewers utilized several yeast strains during fermentation, including one typically reserved for champagne, and a “ninja yeast,” created for its ability to survive and continue fermenting in an environment that has such a high alcohol level."

Now, I have no idea what ninja yeast is.

[Fungi]

Several companies offer yeasts that continue fermenting above the 14% level but don’t know if they are natural or genetically modified. As a general rule, Saccharomyces cerevisiae stops fermenting above that level. Ninja yeasts have black hoods and throw poison laced projectiles.

[P.O.E.]

Ninja yeast is yeast that will only battle the movie’s hero one at a time.