An alternative--and sometimes lazy--way to say "seriously."
This word is commonly associated with South Park's Eric Cartman, although it belongs to Ericaceous.
Other words coined by Ericaceous are fuglah, Ericaceouslah, probablah, maybah, Grah, Lah, bah, pshaw(h), fantasticalah, awesomelicious, and moobstar.
Jane: You're a phat shit bomb!
Anne: Seriouslah? I am?