2-copy it to your Android phone, the file is a "contact.vcf" file.
3-On your Android go the location of the downloaded file and press on it so it can be imported to your contacts.
4-now for the fun part, open whatsapp and create a group with any name you want and add the victim (your friend that you want to prank) to that group and press on the "attachments" then send that contact to the group, now you have to wait like 4 minutes for it to send then you will be fine, don't worry if whatsapp stops responding in those 4 minutes
5-DONE! Now leave the group and when he opens whatsapp and check this new group his Whatsapp will crash.
( Use the "Simpler" app from play store to remove that contact from your phone and