sleepers....how fast and how plain before it is one?

i kind of consider my dart to be a sleeper. yes you can see the cage at some angles. yes it has a chute(but it is removable with ease to conceal it).
so what would you guys consider a true sleeper of sorts? 10 sec, 9s, 8s?? how fast and how simple looking does it have to be?? i think just decieving the masses it is a sleeper.
please discuss and share a sleeper you believe to be one and how fast it is or is gonna be.

mine below for starters high 7s once its worked out. 8s probably in the first couple of hits. yet i onoy intend to run the 1/8 so mid 5s to start mid 4s is the goal.

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