What’s the best prank in uniform you've seen? Comment below!

I was in Salt Lake City with an NCO visiting Mormon Square while off duty from training for reclassification school from 13E to 13D. We decided to do the tour and they hand you these cards to fill out so that a missionary could visit you and try to convert you to the LDS. I stupidly filled it out with my own info, then I look over at the NCO's card and he tells me he's filling it out for one of the troops in our squad and put the armory as the address to visit him at. We finish that tour and then go to Brigham Young's house. We get the cards again, and he fills in another troop's name. I put an NCO nobody in our squad or our battery really cared for on the card. We do the tour and then forget about it for a while. We do drill a few months later and the NCO I went with to SLC comes up to me and says "The Mormons are here!" It all came back to me and since we had to do a drill elsewhere, I stayed in the van we were using for transport and watched as a couple of the guys got these missionaries to talk to them. End of the weekend, the NCO I wrote in ran into me and said it was the best prank he ever had pulled, then my 1SG chewed me out for it due to it not respecting people's religions and such. Either way, it was still the best prank I pulled in service.

Dumping a bucket of liquid nitrogen off the roof of a hanger at Travis AFB as the new airmen come out and tell them yeah it snows here all the time.

I was working as a C-130 navigator and we sometimes transported army troops about S.Vietnam. I built a battery powered reverberator I could connect between the microphone part of the headset and the intercom, radio, loudspeaker system in the aircraft. It was more common for jokes to be exchanged between flight crews and air traffic controllers especially when we transported them to air fields where they worked.
I was usually put on misfit crews because misfit crews not only performed well, but it was easier for me to get along with fellow cultural deviants.
The aircraft commander invited a soldier up to the flight deck to demonstrate the "new robot audio autopilot." With the real auto pilot it was a simple matter to cause the aircraft to turn by dialing a knob on the N-1 compass system. (It would work on the C-12 compass system which has rotating barrels with numbers on them like an automotive odometer with 1/10 degree numbers spinning up and down) The soldier was invited to tell the "robot" to turn right or left whereupon unnoticed in the back of the flight deck I turned the dial on the compass system and with the reverberator replied over the loudspeakers, "Yes, master."
I doubt anybody fell for it but they went along to experience entertainment.

(1968:) In my village in Northern South Korea, Tongudcheon (a/k/a Dongducheon), the "Honey Bucket Truck" came around to suck out all of the village "banjos" (outhouses) every Tuesday. Between all of the kimchi and offal, the odor was horrendous! To "warn" everybody that the truck was approaching, the driver would ring a set of bells mounted above the windshield. The "standing prank" was to send all of the soldiers new to the unit into the village to "find the ice cream truck". The American G.I.s, accustomed to Good Humor and other ice cream trucks and their ringing bells (this was before the invention of the annoying electronic music now being played) went eagerly in search thereof, only to be severely disappointed to find the source of the bells! (It was a hoot, though!)

When I was a grunt in Vietnam I loved dried apricots. I would buy a can of them at the PX while on stand down. If I knew that we would be getting fresh soldiers out in the bush then I would string some apricots on a shoestring and attach them to my belt. When the new guys showed up, The other guys in my squad told them thai I was psycho and that I cut the ears off of dead gooks, which was total bullshit but some of them beleived it. When I took an apricot from my belt and ate it one guy started gagging. In only a few days and they knew that they had been had. It was a harmless prank, no one was hurt and it was fun at 19 years old. As a footnote to this I still called apricots ears when my daughter wea young. She got in trouble in school for calling them ears even though she knew they were apricots.

My roommate would tie all my boots and shoes together and tie them to the bunk. He once filled my PT shoes with dippity-do hair gel. I sewed the fly shut on all his boxers and once sewed the legs and sleeves shut on all of his cammies.

One time, when we were doing "base duty" (we would do a month of driving officers around, raising and lowering colors, any funerals, chasing prisoners to the brig or d-cell, etc.) we had a canoe boat 2LT who was a total prick. He would stand in front of the formation and berate everyone, while pacing back and forth and cleaning his sunglasses. One of us got ahold of his cleaning cloth and sprayed it with mace. Every time he put his glasses on, it would make his eyes water. My Gunny would put a little tissue paper inside his dress blues cover band, every night. Making his cover smaller and smaller. On the last day he pulled all the tissue paper out. The 2LT's cover damn near hit his shoulders, it was so big.

Here's some:
1. A cast cutter looks like a Moto-Tool with a little circular saw, but it just rotates back and forth, chews through plaster but doesn't harm skin. We had one in the shop to fix, and when a new guy came in, he got an unexpected demonstration on his forearm. No pain, but very frightening. Seemed hilarious at the time, but now I think it was cruel.
2. On watch in maneuvering room during submerged ops playing catch-me with surface forces, my sneaker-clad foot slipped on the linoleum, squeaked. The other controllerman thought it was a sonar interphone ping telling us we were detected. So I did it a few more times, just to watch his concern. It was amusing, but he was a nice guy, so I finally fessed up.
3. This surface ship I served on had a supply department, with a storeroom and clerks. We presented requisitions and got parts. One of the guys in our shop said he wished we could requisition 8 hours sleep. So I filled out the form, got our division officer to sign it amidst a bunch of others, and sent a man down to pick it up. The clerk couldn't find it, and got really puzzled, and our div officer just smiled when it got back to him.
4. In the early days of nuclear power prototype operation in the Idaho desert, the locals were proud that it was in their turf, but a little concerned about the mystery of radiation. Once, when there was a huge upswing in the desert's rabbit population, some of the crew of a Navy prototype captured plenty of them, spray-painted them wild colors, and let them loose. There was a major panic about the radioactive rabbits being seen in the desert.

Had an E5 who worked for me who was due to PCS. He had performed well and his SNCO and I submitted him for a Commendation Medal. This was before word processors so we had to type the presentation certificate, with the narrative perfectly centered, and absolutely no errors and no corrections allowed. As you might well guess, this took several tries so we had several certificates that didn't meet muster before we got one right. Okay, submitted package, got it approved, medal awarded and certificate presented at Commander's Call. Afterward, we had a small reception with cake and coffee at the office. My E5 had placed his fancy new certificate front and center on his desk and was enjoying cake. Asked my SNCO to get him away from his desk for a moment and while he was gone, switched his "good" certificate with one of our earlier tries. He comes back to office and is admiring his certificate when I come in with a sloppy dripping wet cup of coffee and casually set it right in the middle of that certificate. Here, man, I brought you some coffee for that cake. I thought he was going to go apoplectic on us.

We were doing an ARTEP of the 16th MASH out of Fort Riley in August 1987. One of my sergeants had caught a garter snake, and we had a cooperative specialist who was a simulated patient. So we moulaged her hand to look like she had received a snake bite between her thumb and forefinger, then had her put the snake in the cargo pocket of her BDUs and transported her to the MASH. They brought her into the receiving room, and they started their triage process. Everything went fine until they asked her if she knew what type of snake it was. At which point she replied "no, but I have it right here," and proceeded to pull a *LIVE SNAKE* out of her pocket in the emergency room tent. I have a picture I snapped exactly when she did it of all the ER staff recoilng it horror--it's great. The ER doc, to his credit, quickly recovered, calmly took the snake and handed it to one of his medics and said "would you please take this out of here?" and then continued with his assessment . . .

I knew some Corpsmen who, when an MP came on sick call, would take the guy's shot record and one of them would leave with it.