No, "most catchiest" would be redundant. Catchiest already makes a thing the most or best. Use most only when you are not using a word that already implies most. It was the catchiest slogan the Republicans could offer. It was the most catchy line he could think of.
As we find with most songs, in poetry
A post on the website, Huffington provides a list of the most popular wedding songs according to Spotify, the commercial music streaming service. The results were interesting as the most popular wedding song was "Party Rock Anthem" by LMFAO.
There are many songs that play during Cadillac commercials. One of the most popular songs that have been played during a Cadillac commercial is Tyler Cassidy's song "Christmas."
It is either "Shakawkaw" or "Dracul" most likely.
For lyrics go to the hetalia wiki and for actual songs either watch the episodes or you can find most on Youtube.
you can find most of it on youtube, and some on specialty sites - but most animes have no official english versions of their songs. most will be fan-made or vocaloids.
There are a few songs with Milo's Song in the title, but you can find most of them on YouTube.
You can find listings of the most popular songs of the 1950's on Wikipedia or Billboard websites. The website Rate your music also have listings of music in the 1950's.
Chris Sullivan is the voice of the camel in the Geico commercial Happier than a Camel on Wednesday. Some people find the voice annoying, but most find this commercial their best one yet.
Most commercials use music to help draw in a potential customer. Car commercials use jungles and background music as well.
Personally, I don't find any of them to be particularly scary in any way. Maybe you can point out what it is about them which you find scary, and an answer can be given based on which songs have the most of those elements in them.