Annoy Patty!
Probably the funniest character in the series besides Dante. I couldn't really come up with anything for the other characters, Patty was kind of hard. Sorry…
Replace her drama show with something inappropriate, like Elfin Lied (Good anime I'd recommend it)
Tell Dante she's watching bloody anime
Watch Dante stare at it while Patty yells at him
Break the TV
Fatality!
Burn her stuffed animals
Tell her you hope she never finds her mom, lives with 29830498342 cats, and dies alone after being mauled by demons just to see her reaction
Tell her to have a nice day afterwards!
Eat Dante's ice cream before she does
Remember how she went into that hotel in the last episode or around that time? Order room service and put it on her mom's tab.
Ask if she wants anything and watch her get yelled at when her mom finds the bill
Remember the opera house from the beginning when she mistook that demon for her mom? Tell her you see similarities between the two
Boo them on stage
Throw tomatoes
Pull the curtain up while Dante's killing the demons and mentally scar her with the sight of blood gushing from the demon's corpses
Laugh
Hope the blood ends up on her face
Laugh if demon blood gets all over her
If it gets on you, freak her out by licking it off of you
Watch her vomit
Say you're cooler than Alucard
Run when angry fans and Alucard (possibly the swordsman priest guy whose name I can't remember too) chase you (please tell me sword priest guy's name before you die))