What do you call the something that's on-the-tip-of-my-tongue-but-I-can't-think-of-the-word-for-it?

You know. Thingum (bob). Whatchamacallit. Doohicky. Widget. Ineffable thingie.

A couple of threads where we've mentioned this sort of thing before:
https://wordcraft.infopop.cc/eve/forums?a=tpc&s=441607094&f=932607094&m=4546010572&r=6176006572#6176006572
and https://wordcraft.infopop.cc/eve/forums?a=tpc&s=441607094&f=741603894&m=7656064085&r=7656064085#7656064085

whosamawhatzit
thingamabob or thingamajig

I like jheem's addition of ineffable . . .

I, too, remember those old threads, and words like "thingamabob." However, I didn't think that was what Shu was getting at. I wonder if there is a word for those times when a word or song or whatever is right on the tip of your tongue...but you can't think of it. It is so annoying! I imagine there is a neurologic word for it, at least...it's right on the tip of my tongue...but I can't think of it.

[Yeah, yeah, and I will be proactive and acknowledge...just for jheem...that everything doesn't have to have its own word. ]