Hmmm, looking at the scars on my hands I can recall at least two stories.
Once I held a razor blade the wrong way and pushed down to scrape coraline off some glass but instead just gave myself an owwie.
Had to get stitches apparently. Apparently 4 stitches if the scar is to be believed.
Another time I was trying to take apart an overflow standpipe and when it finally popped loose the upward momentum carried the back of hand straight into a vermetid snail casing in the overflow and gashed the back of my hand a bit. Stupid vermetid snails.
Once when working in the tank with the halides still on I bumped the back of my head into the lamp and could hear sizzling. Also, on an unrelated note, apparently I am bald.
Which reminds me of a time I leaned over to pick up some reef gear on the floor, and stood up and bumped my head into the corner of the HRV that was hanging beside the tank (before I had walls in the basement). Left a goodly sized chuck of hairless scalp in the metal and had a triangular scab on the back of my head for a few weeks. No idea if the scar is still there. I never look at the back of my head. That lets me believe I am not as bald as people try to tell me.
None of my injuries however can really touch the grievous injuries my house has sustained as a result of having reef gear in the house (or carrying and subsequently dropping reef related gear in the house). I recall one time I dropped a dehumidifier (damn those things are awkward) and it richochet'ed down the stairway punching little holes in the drywall on alternating sides of the stairwell. I am certain that were it not an inanimate object it might have been giggling along the way down too. "Yippeee! I am free! Whee!".