Ŝarkasmo: If you have long teeth (Shark-asmo).
Sarkastmo: If you expect people to choke when they scrap under the surface of your contributions (sarki+astmo)
Sarkasmono is possible in a forum handling economy.
Carkasmo is good if feel chosen by God.
Making “pun” words in Esperanto is no fun… It’s too easy.
I find Sarkasmo quite clear, and won’t change it unless somebody used it already.
Remuŝ