The online comments were unusual on the site that usually focuses on official statements by al-Qaida and other militants. Commentators, who must be registered members of the site, frequently post their opinions, but normally the topics are humorless.
But on Tuesday, one commentator, called Dark-Side, sarcastically urged followers to offer condolences for the cat.
"For God's sake, could someone tell us where the wake is to be held?" the online commentator wrote.
A few also poked fun at Arab leaders allied with the United States.
"This is not the right time to die. It is a dilemma for the Arab leaders at this time because they are busy and have to leave the region to offer condolences" in Washington, wrote another commentator.
But others objected to discussing such lighthearted topics because of the Israeli offensive in Gaza.
"We are sad at this time and publishing this only increases our sorrow," wrote a commentator.