He looked at the lock over his heart, and then looked down and spotted a key, seemingly its mate. He pointed to it and asked what it was for.

His host looked at it and picked it up, holding it up lightly in his hand.

"What, you mean this?" he said with a smile, chuckling nervously.

---
An entry for the Seventh Sanctum contest "Twilight of the Vampires": [link] The rules said to be "different" (and not much else), so after picking his name, I drew this in a sudden fit of inspiration.

Bernardo Lovelock is a toon bat, born in Scotland, who long ago had a deeply serious romantic relationship with a woman he loved very much, which unfortunately ended with him getting dumped and his heart broken.
Wanting to forget the pain, he placed a magical lock over his heart, which he attaches to his jacket, so that his heart would stop beating and prevent feelings of sadness, regret, loneliness, and most of all romantic love. He feels everything else, though, especially fear.
The most unfortunate effect of this lock was that he was forced to become a vampire in order to stay alive. He also can never go any further than ten feet away from the lock, or else it would cause him pain- so while he can take his jacket off, it must stay at his side at all times.

Over the years, he's gotten very used to living as a vampire, living in a castle that normally rejoices in escapades of a macabre nature with his many spooky friends. Ordinary people would still consider him to be a scary freak, though, despite not being evil. But he's still a very tense and nervous fellow who's easily frightened, especially if you bring up the matter of the key that unlocks his heart.
Should his heart ever be unlocked, he fears that it would start beating again, and that he would fall into despair and fits of hopelessly sappy daydreaming.

UPDATE: For further insights into his personality, see this mock interview: [link]

Seriously- this is the very first time I drew him. He just came out this way... after freely associating things with the name "Lovelock" and my favorite horror films, out popped all these symbolic objects that I couldn't readily explain. It was all sort of stream of consciousness.
So for the next few days, I found myself needing to draw other sketches of him in order to fully realize the details, based on this one drawing. I knew what I wanted out of his personality and design- I just had to get it down on paper. Also, I needed to have all of it ready before I could start coloring him.
So I really could only put his backstory into words until right before I started coloring him, once I tidied up the feelings and associations I had attached to him in my mind.

I took a lot of inspiration from cartoons and comedies that were based on macabre humor, especially from the '60s and '70s.
I'm actually not sure what to do with him- I'm thinking he'd mostly be a spokesperson for my love of old-school horror.
Normally I wouldn't have introduced an original character of mine here without copyrighting it first, but this being a contest and all...

The sketch was done in pencil, and the colors were done with colored pencils and Crayola crayons, with some further tweaks in Photoshop. I've always wanted one of those huge boxes of Crayola's complete line of colors, because you can do so much with them... I had been planning to take crayons outside of the realm of children's drawings, and use my knowledge of painting and light and shadow to realize the crayon's full potential.
...And I must say, I've really enjoyed it, like I always thought I would. Crayola crayons are awesome!!

~Fatal hilarity