Slyboots, initially known as Sam Sinister in North America, was a villain in Adventurers Egypt theme. He was the partner of Baron von Barron. Both of them were out to follow Johnny Thunder and get the treasure for their own uses before he could. Slyboot's personality was never expanded on much, and he dropped out of set releases after Egypt, with Baron von Barron becoming the main villain. However, he still appeared regularly in video games and other Adventurers media.