Answer Kings and knights come immediately to mind. For the macabre, a killer might also work.
Karate Instructor / Participant King Tut King Henry the VIII (or any king you can think of) King Kong kangaroo koala bear
Khartoum
An insect that starts with k is the Khapara Bettle.
kick
Kool-Aid
Kilometro Kilates
Comet Kohoutek
karate kid, kola,
Kitten and King Kong are fancy dress costumes. They start with the letter k.
kinetics (also in physics).
karrot?kake?kat? haha not really You could though :) kitty (kitten)? King Kong?
You would say : des costumes d'Halloween, des déguisements d'Halloween. Costumes obviously means costumes, d'Halloween means "of Halloween", so literally it is "costumes of Halloween". You would pronounce it Coz-toome d-all-oh-een.