One had some sort of fiendish fellow, with a mustache, living with some sort of horrible creature in his basement. His chauffeur was sometimes asked to feed it, which was evidently an unpleasant affair. His schemes were constantly thwarted by a team of teenagers, as in all such shows, and in the end the creature was released upon him (all we saw was a claw of some sort appearing at the side of the screen.)
The other I remember little of except a very odd scene. It may not even be a kids show at all. Two men are chasing two teenagers, the teenagers escape by sliding down tunnels of some sorts. The two men pause to turn into some sort of hideous, green, slimey creatures, that then proceed to slide down the tubes after them.
Sounds strange, but such things that I’ve remembered in the past have held to be true.