A cartoon convention since the 1930s, the pentagram, or more often the star outline, is often incorporated with other symbols to represent violence, pain, or a sudden blow.
Illustration detail from "Tess Trueheart Kidnapped!" September 6, 1933. reprinted in Dick Tracy The Thirties Tommyguns and hardtimes. Chester Gould (1900/11/20 - 1985/05/11) Herb Galewitz, Editor. Secaucus, N.J. : The Wellfleet Press, 1990. ISBN : 1-55521-621-8. 285 p.