Oof

Oof, also known as the Roblox Death Sound, is the only good part of Roblox. A Roblox character will utter 'oof' when they die in-game, whether it be from some Bacon Hair slapping you with a default sword, because they fell off the map because it's so broken, or just from the sheer embarrassment of being seen playing Roblox. Oof has been superimposed to just about every video where something receives damage in any way. 
Because of the sound they make, Roblox characters are sometimes called oofers, ooftards, and oofsicles. Roblox is sometimes called "that game where it goes oof". And Robux is sometimes referred to as oofcoins or oofbux. Oof has also been speculated to be the sound humans make upon death, but only they can hear it. This theory has yet to be proven.