Haha, loldemort !
Your brother said, "Damn, that's so stupid". Then I say, "Yeah, that's so LOLDEMORT!"
You are such a Loldemort!
As a verb, it is the act of laughing so hard that some sort of magic flies out from your mouth, nose, fingertips, etc.
He loldemorted so hard he left a charred spot of ashes where the corner grocery store used to be.
"What did Batman say to Robin before they got in the car?"
"Robin get in the car. Loldemort!"