The Collaborative International Dictionary of English v.0.48:

Scrog \Scrog\, n. [Cf. Scrag, or Gael. sgrogag anything
   shriveled, from sgrog to compress, shrivel.]
   A stunted shrub, bush, or branch. [Prov. Eng. & Scot.]
   [1913 Webster]

The Jargon File (version 4.4.7, 29 Dec 2003):

scrog
 /skrog/, vt.

    [Bell Labs] To damage, trash, or corrupt a data structure. ?The list header
    got scrogged.? Also reported as skrog, and ascribed to the comic strip The
    Wizard of Id. Compare scag; possibly the two are related. Equivalent to 
    scribble or mangle.


The Free On-line Dictionary of Computing (30 December 2018):

scrog
skrog

   /skrog/ [Bell Labs] To damage, trash, or corrupt a data
   structure.  "The list header got scrogged."  Also reported as
   "skrog", and ascribed to the comic strip "The Wizard of Id".
   Compare scag; possibly the two are related.  Equivalent to
   scribble or mangle.

   [Jargon File]