What episode was it?
characters
creatures
places
devices
100

Will Byers Disappearance

Season 1, episode 1

100
her original name was Jane

Eleven

100

Descendants of the Demogorgon.

Demodogs

100

Vale of shadows, or, the _____

Upside-Down

100

how the Party communicates

Walkie Talkies

200

Reveal that Jim it taking care of Eleven

season 2, episode 1

200

great at giving hair advice, and is best friends with dustin

STEVE

200
Main Antagonist of season 1

Demogorgon

200

Where the experiments take place

Hawkins labratory

200

how the Party travels throughout Hawkins

Bikes

300

Bob's death

Season 2, episode 8

300

loves puzzles, and hates demodogs.

Bob Newby

300

infects people like a virus, and controls people like a hive

The Mind Flayer

300

the battle of _________

Star-Court Mall

300

what Dustin used to find the gate

compasses

400

when Will gets infected by the mind flayer

Season 2, Episode 3

400

Cleidocranial dysplasia

Dustin

400
these are sprouted all throughout the tunnels underneath hawkins.

the vines

400

where the party usually plays their D&D games

the Wheeler's house 

400

how eleven sees through farther distances

deprivation tank

500

Alexi dies :(

Season 3, episode 7
500

he is very wise...

Will

500

used by the mind flayer 2.0 to create another version of itself

the flesh of the flayed bodies

500

where it all began

the Byers house

500

what Eleven used to find will in season 1

the Heathkit ham shack