Help me invent a word

Today my friend Matt posted this link in response to a status update I had on facebook, it reminded me of something which I have been meaning to follow up with a Blog:

For a long time (back until at least university, three and something years ago) I have been asking people, when it arose in conversation, if they knew of a word to describe these kind of situations:

I jokingly stick my foot out to trip up a friend, they actually trip and break their nose on a table.

Or: I shout "boo" from behind a friend while we're in a bar, in surprise they drop their drink and end up getting thrown out of the bar.

Or: I frape a friend while at their house, suggesting that they have a drug problem, their employer reads it and they lose their job.

These are situations where I do something which is clearly malicious, but the result is far worse than I had anticipated. I am hesitant to use the word accident because that implies too strongly that what happened was an unintentional or unexpected result of my action. If I try to trip a friend up, and they are tripped up, it's not an accident, but I didn't intend on hospitalising them. Similarly with the other two examples, I was certainly being mischievous, but my intention was innocent.

To this day I haven't found anyone who could give me a word, in any language, which describes these kind of situations, yet they arise surprisingly frequently.

So I am asking one last time, if anyone can think of a word, again in any language, which describes specifically this situation. I would expect it to have both a noun: "I can't believe he was thrown out, it was just a ______", and a transitive verb: "Hey, I'm really sorry I _____ed you, I can't believe your boss thought it was serious".

If we still can't think of an existing word, then I propose I invent¹ a new one. In doing so I'd like for it to have some reasonably sensible etymology, so please put forward any suggestions if you can. Perhaps we can vote on it :)



¹ I can't really post this without also admitting that I have a motivation for inventing a new word. It is number seventy of the 101 Things To Do Before You Die: "Invent a Word That Makes it into the Dictionary".