(written from a Production point of view)
Emmy-Lou was a Russian wild boar that portrayed Worf's pet targ in the Star Trek: The Next Generation first season episode "Where No One Has Gone Before". "She" filmed "her" scene on Thursday 6 August 1987 at Paramount Stage 6.
According to Robert Justman, "That pig smelled horrid. A sweet-sour, extremely pungent odor. I showered and showered, and it took me a week to get rid of it!" (Star Trek: The Next Generation Companion 2nd ed., p. 37) In addition, the boar left a distinctive "spot" on the bridge set which remained until the end of the first season. (Star Trek Encyclopedia 2nd ed., p. 497)