All you have to understand about Mr. Carl is he likes to party, especially if it’ll get them access to a speakeasy. If the series puts the team in a position where they need to get into a similar place, Callen can break out Mr. Carl for just long enough to accomplish that goal.
Sam did reprise this alias to catch the drug lord King in Season 8’s “Queen Pin” (and got the job done), but we wouldn’t mind seeing him in a similar role, perhaps with another name, at some point in Season 11.
As we know, Hetty has had numerous aliases over the years — remember all those licenses in her desk? — but it has been some time since we’ve seen her fully immersed in a persona.
There’s not much to this old alias, and it did stem from Deeks just deciding he’d call Kensi “Fern” during a case. In fact, Fern could be whoever she needed to be for a case, but the callback with the name would be a bonus.
Eric and Nell (Eric and Nell)
The couple went undercover at a couples’ retreat in Season 8’s “Getaway,” and perhaps one of the best parts is that they didn’t have to hide much about themselves (other than their jobs, of course). Put these two undercover again in roles where they can focus on the mission at hand, and they’re sure to excel again. (We do have to wonder how Eric’s upcoming mission will affect him, however.)
Highway Patrol Officers (Sam and Callen)
It was amusing to see these two donning the uniforms considering their daily casual wear and other undercover assignments that put them in suits.
We saw Nell go undercover as Hetty in Season 6. The team took care of people trying to kill their operations manager while she was in D.C. It’s a ruse that only works if someone’s behind her, but wouldn’t it be something to see Nell and Hetty use that to work together in the field sometime?
Max Gentry (Deeks)
Perhaps what makes this alias stand out so much is its connection to Deeks’ past. Though he has clearly left that behind, it might be interesting to see if anything about Max has changed over the years.
One thing that the NCIS: Los Angeles team is especially good at is pretending to be what they're not. (Consider their base of operations — you wouldn't think the "condemned" building would be home to a federal agency, would you?)
Over the years, each member of the team has gone undercover, some more than others, and a few of those aliases have been quite memorable.