The centerpiece of Herod Sayle's office is his giant Portuguese man o' war, better known as Physalia Physalia. This "shimmering, pulsating mass of white and mauve" (7.25) is a twisted reflection of its equally twisted owner. Shudder.
Herod Sayle goes on a long rant about the nature of his pet when Alex first arrives at Sayle Enterprises. He explains that it "drifts on its own, ignored by other fish" yet is "silent" and "demands respect" (7.32). It's not hard to see how this relates to Sayle, who Alex has just described as having eyes like "tadpoles before they hatch" (7.27). Instead of poisonous tentacles, Sayle just has lethal henchman.
Instead of wielding his power in flashy ways, Sayle prefers to work beneath the surface and mask his true intentions. Sayle had convinced the entire world that he was nothing more than a philanthropist, but anybody who looks closely can see that his stinging cells are armed and ready to strike. Luckily for Alex (not to mention the entire country of England), both Sayle and his little pet meet the same fate—thrown from their protective enclosure, they both realize that they aren't tough enough to make it in the outside world.