Clotted cream is a regional speciality of Cornwall and Devon, down in the extreme south-west of England where folk are strange, and the stories are stranger.
You take some ordinary cream and you gently heat it until you have evaporated as much of the liquid part as you can. The result is clotted cream. Yummy. It is a light yellow colour because it is halfway between cream and butter. It is thick enough to spread but sort of fluffy. Traditionally you eat it spread on scones (I suspect 'scones' means something different in the US - most things do!) with jam on top. A Devon cream tea consists of scones with clotted cream and jam, strawberries and, of course, a nice cup of tea to wash it all down. (Ed: There is no such thing as a 'Devonshire' cream tea, blues, as the wikipedia article says, because there is no such county as Devonshire - thought I'd just make that clear in case you make some terrible faux pas in the future.
)You can also make it into ice cream.
Clotted cream with blood is probably not impossible to find if you believe all you read about Cornish people. Tourists ('grockles' or 'jaspers' as they are known down there) are said to disappear occasionally under strange circumstances.
The Cornish are an odd lot, isolated on their tiny peninsular. They have their own history and language and are reluctant to call themselves English. They have their own flag too - which is pretty sinister: it's jet black with a vertical white cross on it. Clearly people with a flag like that are capable of anything.
(mind you, we were as well!)