This one is sung by Misael, if that isn't obvious by the Alit and Vector bashing. Although Alit does sing a little in the last stanza.
Deck the halls with tons of green things
Fa-la-la-la-la-la-la-la-la
Alit is being a complete moron
Fa-la-la-la-la-la-la-la-la
Dumon's reading, Gilag's snoring
Fa-la-la-la-la-la-la-la-la
Vector's killing little reindeer
Fa-la-la-la-la-la-la-la-la
Dumon's baking gingerbread cookies
Fa-la-la-la-la-la-la-la-la
Gilag and Alit are now drooling
Fa-la-la-la-la-la-la-la-la
I slipped and fell on a stray pine cone
Fa-la-la-la-la-la-la-la-la
Why do humans bring dead plants indoors?
Fa-la-la-la-la-la-la-la-la
Vector dumped red paint on my head
Fa-la-la-la-la-la-la-la-la
He is going to be so dead
Fa-la-la-la-la-la-la-la-la
Summoning Tachyon Dragon
Fa-la-la-la-la-la-la-la-la
Vector's running for his life
Fa-la-la-la-la-la-la-la-la
Christmas is a stupid holiday
Fa-la-la-la-la-la-la-la-la
Dumb songs, dead plants, and stuff in boxes
Fa-la-la-la-la-la-la-la-la
But Misa it's the time for giving
Fa-la-la-la-la-la-la-la-la
Shut up Alit, you know nothing
Fa-la-la-la-la-la-la-la-laaaaaaaa!