BRAINIAC

Why is Barney evil? You may ask. Some will say "That's my favourite show!!!" 

But, he is a threat to the world.

The government of some countries seek him to ultimately destroy him.

Why?

He owns a mass stash of weapons of mass destruction, plans to cleanse the world of humans to replenish the dinosaurs, destroyed entire cities, destroying landmarks, ... ... ... ... ... ... ... ... ... ...

Here's one common Barney 'insult'.

1. Barney is well-described with the following phrase:

CUTE PURPLE DINOSAUR

2. The old Latin Alphabet used the letter 'V' in place of 'U', therefore the above phrase is modified to:

CVTE PVRPLE DINOSAVR

3. Letters that do not represent Roman numerals are removed:

CV-- -V--L- DI----V-

4. Add up the Roman Numerals of the remaining letters:

C + V + V + L + D + I + V

100 + 5 + 5 + 50 + 500 + 1 + 5 = 666

And, 666 is the number of the beast, the Antichrist, the Devil.