David pulling ... what from the goo?
Looks like what ever was burrowing into the ceiling from low res trailer we already saw. There is a motion gif floating around somewhere.
I'd describe it as a semi-translucent chestburster with a totally different mouth structure. Like a round orifice that opens like a sphincter and has a second extending appendage (like the alien tongue) only it has a singer at the end.
David either is pulling up four of them, grouped together ... or it's one and he's pulling up by it's needle tongue ... which will be how he pricks his finger ... (?)