According to their official website, Nationals of any country can obtain a visa on arrival for a maximum stay of 45 days. but, i heard they deported some travelers citizens of pakistan!
so i didnt want to take risk, while i was in Antananarivo, madagascar. i visited the embassy of comoros in Antananarivo, the Counselor asked for so many documents. then i asked about express visa! he replayed it will cost me $100 (including the visa fee which is $50). i gave him 1 personal photo and my passport, i got my sticker visa afternoon! 3 months duration to activate my visa, single entry for 45 days.
couple days later i Flew from Antananarivo, Madagascar to Moroni, Comoros.