"MUCUS plug" again.
The Big Bang Theory Season 11, Episode 16
Oh, I watched a video
of the hagfish producing MUCUS,
The Big Bang Theory Season 9, Episode 9
Has your MUCUS plug popped out?
The Big Bang Theory Season 11, Episode 16
A hagfish can produce enough MUCUS
to fill a bucket in a minute.
The Big Bang Theory Season 9, Episode 9