Garden Discovery

I was digging a hole in the garden until I found some coins! I was about to tell my mum when I remembered I was digging a hole in the garden.

Explanation

Experiment

The humor comes from the dark implication that the person found the coins in a grave that they were digging. The person had forgotten they were digging a grave and not just digging a hole for fun. They were going to tell their mom about the coins, implying a lack of understanding about how they got there.