You're looking for a treasure, but no normal treasure... a treasure that's a stash of energy. Not gold, money, or anything like that. Imagine yourself finding it, and opening up a treasure chest. Out bursts a spirit ball of energy like you've never seen.
As you reach inside the energy spirit, you feel something hard inside. It's a large key (き) that gives you access to another treasure.
Currently there are no similar looking kanji which exist in the WaniKani learning system