By John Hertz: 

     Sheem made one of us;

     Punning Robinson, for two;

     I can’t forget Tub;

     Descent had Niven and Barnes.

     Really, this is a marvel.

Acrostic (read down the first letters of each line) in unrhymed lines of 5-7-5-7-7 syllables, something like Japanese tanka.  Sheem, The Witches of Karres ch. 7 (J. Schmitz,1966); Robinson, e.g. Callahan’s Crosstime Saloon (1977); Tubby Tompkins, see Icons of the American Comic Book v. 1 p. 453 (R. Duncan & M.Smith, 2013); The Descent of Anansi (L. Niven & S. Barnes, 1982); marvel, e.g. Amazing Fantasy 15 (August 1962).