DESU should be a dynamic keyword that will serve multiple purposes in different contexts based on the number of repetitions of the keyword.

In the singular case: Suppose we try to open a file that doesn't exist. An exception should be thrown in order to prevent abnormal program termination.

HAI
CAN HAS STDIO?
PLZ OPEN FILE "NOTHERE.FILE"
  AWSUM THX
    VISIBLE FILE
  O NOES
    DESU
KTHXBYE

In this example, DESU serves as a break statement, which would simply pass program control to outside of the control block (below KTHXBYE)

In the double case: I don't believe threads have been implemented as of yet, but in the case that they are, calling DESU DESU should act as a thread death/join (or, as a syntactical difference, one could call Threadname DESU.

HAI
CAN HAS THREADS?
CAN MAKE THREAD THREAD?
  AWSUM THX
      stuff to make THREAD run 
      THREAD DESU
   O NOES
      DESU
KTHXBYE