Sending a new apprentice for a bottle of blinker fluid is a tradition. Done well, it breaks the ice and makes someone feel part of the team. Done badly, it makes somebody feel stupid on their first day. Here is how to keep it on the right side.
1. Pick a harmless errand
The best pranks have no safety angle at all. Blinker fluid, a sky hook or a left-handed screwdriver all work. Never send someone to do something that involves real tools, heights, chemicals or the general public.
2. Keep the cast small
Three or four colleagues are plenty. If the whole building is in on it, the new person feels watched instead of welcomed.
3. Time-box it
One errand, one or two stops, and the reveal by lunchtime. A prank that lasts all day stops being funny after an hour.
4. End with a laugh and a real task
When the joke is out, explain the tradition, tell your own story, and give the person a real job to do. That turns the prank into a welcome.
5. Know when to stop
If the person looks upset, tell them straight away. Everyone is different, and some people hate being the centre of attention. A good team notices and adjusts.
Looking for a gift instead?
A great alternative is to give the new person a parody part as a welcome present. Our shop is full of products that sound real and are not, from the Dark Bulb to the Muffler Bearing. See also: 15 classic fake parts and prank errands.

