So somebody says a wish then another person replies trying grant the wish but in a bad way. For example:
I wish I had a unicorn

Reply: Wish granted but it runs away 2 seconds after you get it and you never see it again.
I'll start

I wish my internet was faster

Granted but your computer then gets smashed by the unicorn who comes back for food

I wish i had lots of money

Granted, but if you spend it you will blow up.

I wish I had a burger...

Granted but i poisoned it for making my money blow up

I wish i had some chocolate

Granted but it is full of crawling beetles which leave horrible trails of puss. Want to eat it lol?

I wish I was magic

Granted but you accidently cast a spell on yourself that means you can never eat chocolate again! Ha!

I wish i could eat whatever i wanted and not put on any weight

Granted but everyone is so jealous of you that they throw a lot of mouldy pumpkins at you.

I wish that I never got tired

Granted but you have to sleep for 23 hours every day!

I wish my iPod had more storage.

Granted, but every song you put onto it instantly turns into a cheesy pop song from the 90's!

I wish I had superhuman powers!

Granted but you accidently lift up your house and drop it into the sea.

I wish I had some lemonade

Granted but the lemonade falls onto the floor from midair and gets quickly evapourated by the sun.

I wish I had a vampiric dress.

Granted but it dissolves when sun shines on it so you can only wear it when it is dark and nobody can see you

I wish I had some apple juice

Granted, but the apples used to make it are rotten and give you food poisoning

I wish I didn't have to go to work to earn money

Granted but you become poor as you earn no money and your goverment stops giving you money.

I wish I had a bigger house.

Granted but it is so big it takes you four years to get from your bedroom to your living room!

I wish my computer had more memory...

Granted but you can eat nothing else but cheese for the rest of your life

I wish I had some apple juice

Granted but it falls from mid-air onto the floor only to be quickly evapourated by the sun.

You need to make a new wish

^ Sorry I forgot.

I wish that I had red hair again.