Basically, this is rather childish but at the same time, it can be quite fun for a few minutes.
think for a second that you've typed in /nick (!N) because you want to confuse your contact somewhat ... that's all great apart from his font face, size and colour are different to yours
Could you possible code in a (!NF) for example to copy your contact's font details exactly so you can make it looked as though you're making them say something ... or if you both share a contact then you can even more childishly talk to the shared contact with these details and see how long it takes for them to cotton on.
I know it sounds stupid but it can be a lot of fun ... hope what I've actually said makes sense as well !!
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