Sometimes the monsters in Doctor Who aren’t the real villains of the piece. They’re just animals or beasts that are unhappily caught up in affairs they don’t truly understand. Oh sure, they’re terrifying to look at and definitely very deadly, but they’re not intent on taking over an entire planet, they don’t know how to lay a trap for a Time Lord and frankly, their evil cackles are just lame.
What they are good at is hunting and killing and eating their prey, and shrieking in a scary fashion. It’s nothing personal, that’s just what they do.
The Drashigs are that kind of monster. The only reason the Third Doctor and Jo Grant even find out they exist is because some travelling showfolk aliens have managed to swipe them all into a device called a Miniscope (it’s all in Carnival of Monsters). The Miniscope is a miniaturisation device that shrinks its inhabitants down to a very small size, and then lets them fight against each other.
Some of the inhabitants are sentient beings, like the crew of the boat the TARDIS lands on at the beginning of the story. And some are not, like the seamonster that keeps attacking that boat, or indeed the Drashigs themselves. They’re just these swamp-dwelling lizard dinosaur creatures that hunt using their sense of smell. This allows the Doctor and Jo to witness the full rearing horror of one at fairy close range, without being detected.
Here’s a Drashig in all of its brutal glory:
And here’s how you deal with one, should you be in the unfortunate position of being attacked. You get your sonic screwdriver out, and make mud explode (best not to ask, the answer will only be confusing) and when that fails, encourage a reluctant carny with a giant hand to bat them out of your way:
Sadly, once that swatty hand had been involved, the Drashigs followed the time-travelling twosome’s scent into the circuitry of the Miniscope itself. Now the Miniscope is owned by Vorg, the travelling showman with the see-through hat, and he’s found out that if anything escapes the Miniscope, it returns to its normal size. So when the authorities on the planet Inter Minor suspect him of being a spy, it’s not long before scheming representatives at his tribunal plot to use some freed Drashigs to help them take over the planet.
Naturally the Doctor is having none of it, and once he escapes from the Miniscope, forms an alliance with Vorg. The Doctor goes back in to prevent the full carnival of monsters from escaping, and Vorg kills the two Drashigs that do get out. There’s a bit of to and fro with some broken machinery, and Vorg gets the Doctor and Jo out of the Miniscope in the nick of time, sending all the monsters back to their natural habitat.
And the Drashigs? Well apart from the two dead ones, they just go back to what they do naturally: rearing up, shrieking, and being scary. Their place in Whovian history assured, but also ignored (by them).