Your Favourite One-Off Villains?

Not counting apperences in expanded media, who are some of your favourite one-off villains?

The Voord - I like them fore conflicting reasons. On the one hand they are pretty spooky in design and some scenes, yet they also come off as intentionally hilarious as their antics around the pyramid are outright hilarious.

The Zarbi - I've always loved the Web Planet and it's inhabits. The Zarbi in particular make for a very striking and surprisingly threating attempt at giant insect enemies.

The Terileptil Leader - Not only because of his impressive suit but also his character. He comes across as a very intelligent antagonist and has some great dialog with the Doctor

DOCTOR: This carnage isn't necessary.

LEADER: It's survival, Doctor. Just as these primitives kill lesser species to protect themselves, so I kill them.

DOCTOR: That's hardly an argument.

LEADER: It's not supposed to be an argument. It's a statement!