The Tetraps are humanoid bat/wild boar hybrids with four eyes, a forked tongue, furry bodies and an addiction to blood plasma. Unique, ridiculous but impressive is perhaps the right combination of words to describe them.
Sleeping upside down like bats, they are short sighted (one eye on each side of your head can get confusing!) but what they lack in sight they make up in threat: they can dispatch their victim by injecting paralysing poison through their tongues. Ouch.
They were employed by The Rani (Kate O’Mara) a Time Lady science genius, whilst she was conducting brain experiments on the planet Lakertya. They bullied and enslaved the locals (naturally) and enforced the will of their mistress.
Their impressive, imposing design begs for a 21st century update, perhaps applying them with contact lenses next time!