"Come Back, Little Arnold" was Irene Arranga's third appearance as Mary Johnson, the object of Arnold Horshack's affection, so frightened of looking foolish in front of her that he accepts a free bottle of courage from bad penny Carvelli. Arnold's uncharacteristic aggression and rudeness has everyone on edge, actually ripping into his fellow Sweathogs for making fun of him all these years (though all done in fun, he's got a point). Eventually his drinking problem is revealed to teacher Jean Tremaine, the second and final appearance of Della Reese in place of an absent Julie Kotter. His friends try to reason with him but his drunk is not the fumbling stumbling kind but a very real, and frightening visage. The climax at the prom is positively electric, setting the stage for the series finale, though few viewers were still watching at this very late stage, Julie, Kotter, and Barbarino all absent here (this was the last appearance for Carvelli and Murray).