You have fingers in the thousands and while looking up at the sun you decide you want to insert them in there.
You insert one finger, it burns up immediately, and its soul (そう) comes flying out screaming for a moment before it disappears. Hmm. You insert another finger and as it burns up, another little soul comes out screeching, "WHY WOULD YOU INSERT ME IN THERE!" and is gone.
Currently there are no similar looking kanji which exist in the WaniKani learning system