Fishing pier.... when tourists catch a Horseshoe Crab, they have no idea what to do or what it is. If you've ever seen the underside of a live one, it's pretty scary looking. I help get it out the net, then get the hook out. By this time there is always a crowd, always.
When picking it up, I'll put my hand close to the legs and all of a sudden start screaming for help and shaking like it's eating me. People always run, no one ever tries to help....
Another harmless one when eating out that my kids love me to do.... you can tell the sense of humor of your server, some are more fun than others,,,, well when they fill your water, wait till they are holding the cup up the air, near your face kind of, when the ice falls out the pitcher into your cup, jump, grab your eye and start moaning. Timing is crucial but works just about every time...
Not too long ago while at a tennis match I was fidgeting with some cut pieces of black nylon rope. After unravelling it, I realized it looked like a mound of pubic hair. So next day at work, (we have a young tough buck who isn't as tough as he thinks he is), I come out of one of the womens restrooms with a fresh pair of nitrile gloves on, and that mound of brillo pad in my hand saying, "my gosh look at this, look at what I found on the floor in there", then just smashed it in his face.... I was laughing so hard while running laps around the truck with him chasing me, I had to beg him not to punch me when he finally caught me

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Recently pulled a lifeguard training doll out the dumpster, looks like about a 6 year old... some red and black sharpies made it really freaky.... I call him Dusty.... Dusty is going to get some folks here soon.