It means the last Friday in December, right?
How about a formula like this?
From a given date, find the position of Friday from the last 9 days of the year and subtract from 32 to show Friday.
{Date} would also work with "CREATED_TIME()" or "LAST_MODIFIED_TIME()".
 
DATESTR(
  YEAR({Date}) & "/12/" & (32 - 
  FIND("5",
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/31"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/30"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/29"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/28"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/27"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/26"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/25"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/24"))&
    WEEKDAY(DATESTR(YEAR({Date}) & "/12/23"))
  ))
) 
 
 
 
                
     
                                    
            Slightly more concise than the previous answer:
DATESTR(YEAR(TODAY())&"-12-"&(31-MOD(WEEKDAY(YEAR(TODAY())&"-12-31")+2,7)))
                
     
                                    
            Slightly more concise than the previous answer:
DATESTR(YEAR(TODAY())&"-12-"&(31-MOD(WEEKDAY(YEAR(TODAY())&"-12-31")+2,7)))Excellent answer!
I now know a little bit about the use of MOD functions.
                
     
                                    
            Amazing! Thank you @Sho and @David_Skinner !
 
If I wanted to change the output to a MM/DD/YYYY format, what's the best way to do that?
Really appreciate both of your quick responses! 
                
     
                                    
            Thank you so much @David_Skinner !!!