1031 Series

The Halloween Series (1031 / ハロウィン)  is a series of songs made by Machigerita-P. The series consists of songs uploaded on or close to Halloween and has been ongoing since 2008.

Background
Each song (except for Halloween Monster Party Night) has the numbers "1031" somewhere in the song. This is read as "Halloween". Most of the songs also have "lulilu lilala" sung, sometimes more than once. Tt is usually mentioned as a "spell" or "cursed words".