I'm too late. I can't do anything but watch how some men dressed in black suits seize the device.
But would you look at that!
Their car gets hit by a tractor beam from above. They go up into the sky... Higher... Into an UFO... And now they are gone.

The photos that I made are blurred, out of focus and underexposed. I leave them here for the next user because noone would believe me anyway.

I incorporate the pictures into my SCP item entry and get voted off the site for being too bland.
(I'm actually more bothered by your pea-brained use of a black hole, not really something you could just make and especially not something that wouldn't destroy us all if it were.)
I leave a 15-year-old laptop along with the backpack that goes with it to the next user. It works perfectly fine, but requires the previous owner's password.

[I replace the old drive with a new 931 GB drive, Load Windows 10 after disabling telemetry and other objectionable characteristics of the OS as "Group Policy." I add additional memory and leave the refurbished anachronism to the next user to donate to a grade school child in need of a laptop for school.]

I return with my pea-brained thoughts, not understanding Hooyahh's wish of something to give to student. As I just popped out from a dimensional rift. So I leave the useless laptop behind for the next user as well as some instruction books on many things such as "How to eat" by Elington Roggers.

I follow the instructions and try to eat one of the books. It really works! The other books get stored in my pantry.
The laptop seems to be powerfull enough to run older games, so I install Windows XP to play my old beloved games that don't run on anything else. BTW, the BIOS password was "password".

For the next user and/or the child that was supposed to have the laptop, I leave a poem about the unfairness of life.

I read the poem and use it to incite extremely strong negative emotions in myself.

I leave for the next person a jar filled with my tears and regrets

I make ink with the precious tears and write all of the cares down in a journal. I clear an area of brush and debris and make a campfire on a cool, clear and windy moonlit summer night. I place the journal upon the fire and watch as each care vanishes silently and playfully into the gentling breeze. All is well now and all is now as it should be. There is peace and there is grace, yet most of all there is a magnificent hope which I know shall never be lost.

I leave the next user below in charge of the next post.

I leave the next user a puffy leather jacket that I found one morning on a corner curb and I kept it in my closet for a few weeks. In real life, I offered it to a friend but the other friend who was holding onto it forgot about it for a few months while it sat inside a truck at a compost lot; so by the time I met the jacket's receiver again, we pulled it out of the truck and it had moldy spots that were presumably cleaned off. Whoever posts next gets to decide what condition the jacket is in.

The condition is surprisingly excellent; in fact better than new, it's like new.
unfortunately the mold has undergone some form of symbiosis with the jacket making it a knock off marvel symbiont that only covers like 40% of the body.
I leave the other 60% of a body in a dumpster out back for the next person.

While picking Lego out of the grime around this dumpster, I notice the body-parts and alert the Boys & Girls Club right away so they can call the cops. I leave the presumed guilt of this crime to the next user.

(Seriously, their dumpster is a good source of Lego sometimes.)

Walking nearby, I hear some man with lego shout that I caused something. However, I combat the claim and say that Mike's fingerprints are all over the crime scene which he has caused. I also point out that I have stalked him some weeks and that his daily routine is near the dumpster where the crime happened. With a quick window of opportunity of escape, I sprint away and leave behind evidence of the body-parts in the next user's hands. In addition, I was wearing gloves and a mask the whole time, which hid my identity and prints. It any evidence is found against me, it has been fabricated towards the next user.

Hey, at the time of the murder, I was busy getting vaccinated. Everyone in the queue plus the staff who attended and the nurses will attest to that. So my alibi is unbreakable.

After warning the authorities about the finding, I leave to the next in the queue an empty vial of vaccine.

Leaves a smell.

[enters wearing a level 5 Hazardous Materials suit]

[leaves approximately 71 grams of Sasquatch scat]

Leaves extra gas masks for the next user as I leap away