Doodad informal noun
Used to indicate a name of gadget or item whose true name is unknown or has been forgotten.
A: Give me that doodad to fix my car. B: Here you go.
Is this the little doodad you lost, Mark?
I'm afraid that we can't afford to buy that doodad.
If you fall for someone's trick the first time then they are at fault.
Are you going to mess with me again? Fool me once, shame on you; fool me twice, shame on me.