this joke is only funny in spanish so all the joke is said in spanish, soz.
first frame : batman :[]
second frame: joker :[]
third frame: batman :[]
fourth frame: joker :l

first frame: batman: has visto el accidente?
second frame: joker: cual accidente?
third frame: batman: el de mi poya en tu frente
fourth frame: joker: :l

l               ----------                 l
l             l           l                l
l             l           l                l
l ------      l_______l                l_______       =]