the modified version of the exclaimation 'excellent.' Derived from the habitiually said catch word 'ex..cell...ent; so commonly said among those having a devious or sinical speech pattern (mad, insane, mini, evil scientists or surgeons.) Saying Egg Salad just sounds dumb, but once you start saying it you really can't stop sounding really dumb. So Eggsallent is the resulting accepatable word that can be salvaged out of that compultionary "egg....." with the latter, 'sallent' being just better sounding than salad, and still recognized as maybe being the original Excellent.
Robby had grown sick of hearing his son, Bobby, repeat after his favorite cartoon-evil-mini-mad scientist's "Excellent..." response to everything. So Robby asked his son to change it to something a little funnier. So Bobby would say, "egg sallad..." in the same cartoon-evil-mini-mad scientist voice. Then soon, Bobby found out that he sounded really dumb and wanted to say excellent again; but the phrase egg-salad had dug itself entirely too deep for Bobby to not blurt out "Egg", no matter the surcumstance. Hence, Bobby's reaction time to his own mistake always leaves the eggs and transforms the salad, to Sallent.