Pelons are extremely rare "practice pieces" for the early t-shirt designs. Before production was initiated, the image or design was tested on cotton cloth or burlap to determine the color and line accuracy of the piece. Only a few of the "tests" were preserved once the design was deemed acceptable and the t-shirt went into production.
The macabre thespian raged against a grievous affront: the Grateful Dead, pointedly absent from the billing, were busted in New Orleans for marijuana possession. The fine print at the top of the poster indicated that this was a benefit concert for the band.