Soup! is a Befunge quine with a twist: it uses its source code as a pattern with which to generate ASCII art. This makes it massively obfuscated to encode the shape of its output. The actual program is smallish, really.

Source

Here's what it looks like:

      060p070                                                           p'O80v
    pb2*90p4$4>                                                         $4$>v>
  v4$>4$>4$>4$>#                                                        ARGH>!
 <{[BEFUNGE_97]}>                                                       FUNGE!
 ##:-:##   #####*         4$*>4$      >060p>    60g80g -!#v_  60g1+     60p60v
 #vOOGAH               **>4$>^!!eg    nufeB^    $4$4$4 $4<v#<<v-*2a::   v7-1g<
 #>70g>90g-!          #@_^Befunge!!   123456    123456 VvVv!#!>Weird!   >0ggv*
  ^$4$4p07+1g07      ,a<$4<   <$4$4<  <$4$4<    <$4$4< <<#<*-=-=-=-=-*  -=-=v*
   ::48*-#v_>,4$>    4$4$4     $4$4$  4$4$4$    4$4$4$ 4$^*!*   XXXXXX   XXX> 
     BOINK>$60g1-7  0g+d2*     %'A+,1 $1$1$1    $1$1$1 $>^<$     HAR!!!  8888 
        Befunge_is  such_a     pretty langua    ge,_is n't_i     t?_It_  8888 
           looks_so much_l     ike_li ne_noi    se_and it's_     STILL_  ‘88’ 
Turing-     Complet e!_Cam     ouflag e_your    code!! Confu     se_the       
hell_out   of_every one_re     ading_ your_co  de._Oh, AND_y     ou.:-) ,o88o.
 Once_this_thing_i   s_code   d,_rea  ding_it_back_ver ges_on   the_imp 888888
  ossible._Obfusc     ate_the_obfus    cated!_Befunge_ debuggers_are__  888888
   your_friends!       By:_Alexios     Chouchou las... X-X-X-X-X-X-X!   888888
      -=*##*=-           \*****/         9797*  -=97=- !@-*=  *****     ‘"88P’
                                                       *!@-*                  
                                                       =*!@-                  
                                                       -=*!@                  
                                                       @-=*!                  

Output

And here's what it prints when it runs:

      GHIJKLM                                                           UVWXYZ 
    FGHIJKLMNOP                                                         VWXYZA 
  EFGHIJKLMNOPQR                                                        WXYZAB 
 EFGHIJKLMNOPQRST                                                       XYZABC 
 FGHIJKL   PQRSTU         EFGHIJ      QRSTUV    ABCDEF HIJKL  OPQRS     YZABCD 
 GHIJKLM               CDEFGHIJKLM    RSTUVW    BCDEFG IJKLMNOPQRSTUV   ZABCDE 
 HIJKLMNOPQR          CDEFGHIJKLMNO   STUVWX    CDEFGH JKLMNOPQRSTUVW   ABCDEF 
  JKLMNOPQRSTUV      CDEFGH   LMNOPQ  TUVWXY    DEFGHI KLMNOPQRSTUVWXY  BCDEFG 
   LMNOPQRSTUVWXY    DEFGH     NOPQR  UVWXYZ    EFGHIJ LMNOPQ   UVWXYZ   DEFG  
     OPQRSTUVWXYZA  DEFGHI     OPQRST VWXYZA    FGHIJK MNOPQ     WXYZAB  EFGH  
        STUVWXYZAB  EFGHIJ     PQRSTU WXYZAB    GHIJKL NOPQR     XYZABC  FGHI  
           WXYZABCD FGHIJK     QRSTUV XYZABC    HIJKLM OPQRS     YZABCD  GHIJ  
MNOPQRS     YZABCDE GHIJKL     RSTUVW YZABCD    IJKLMN PQRST     ZABCDE        
NOPQRSTU   YZABCDEF HIJKLM     STUVWX ZABCDEF  IJKLMNO QRSTU     ABCDEF HIJKLM 
 PQRSTUVWXYZABCDEF   JKLMNO   STUVWX  ABCDEFGHIJKLMNOP RSTUVW   ABCDEFG IJKLMN 
  RSTUVWXYZABCDEF     LMNOPQRSTUVWX    CDEFGHIJKLMNOPQ STUVWXYZABCDEFG  JKLMNO 
   TUVWXYZABCDEF       NOPQRSTUVWX     DEFGHIJK MNOPQR TUVWXYZABCDEFG   KLMNOP 
      XYZABCDE           QRSTUVW         GHIJK  NOPQRS UVWXY  BCDEF     LMNOPQ 
                                                       VWXYZ                   
                                                       WXYZA                   
                                                       XYZAB                   
                                                       YZABC                   

Theory of Operation

The actual executing code is the first few lines of the source; the rest is padding, even some of the bits that don't quite look like it. The code reads itself and prints it out, converting non-space characters to the appropriate alphabetic ones.

The source is actually meant to be obfuscated. It makes use of quite a few Befunge 97 commands, include some really unusual ones. Many of which may indeed have been obsoleted when the Befunge 98 specification was released.