Clowns are scary. We don’t care who says they’re not. Even the Doctor knew not to trust someone who paints a smile on their face. In the example of Chief Clown, here’s someone who think that getting a laugh involves hunting down and killing anyone who doesn’t like the circus.
It’s an overlooked monster that doesn’t get the credit it deserves. Its origins are straight out of something you’d expect from a 50s Sci-fi movie and it can do much more damage than the average garden weed. It’s the Krynoid and it loves being aggressively green.
The old adage states that ‘justice is blind’ and in the case of the Megara it must be true. For an enemy that can’t be seen properly and are sentient, you’d get the feeling that you would constantly be looking over your shoulder if you felt even a slight presence one was near. The Doctor originally met the Megara in The Stones of Blood and they appeared in one of those instances where the Doctor mistakenly releases the villain. It was only through a big of trickery and double bluffing that he managed to get them from turning him in to a pile of stones.