The best way to learn proper English is to read news report, and watch news on TV. Watching TV shows is a great way to learn casual English, slang words, understand culture reference and humor. If you have already watched these shows then you may recall the words used in the following dialogs.

Midgardsormen,
the world's SERPENT,
Vikings Season 1, Episode 6

Thor will kill the SERPENT
but die from its venom.
Vikings Season 1, Episode 6

A piece combining the power
of the knight, queen and SERPENT.
The Big Bang Theory Season 4, Episode 22

Lava Serpent.
The Big Bang Theory Season 3, Episode 5

I play my Endless Serpent,
Raj will play Ecstatic Frenzy...
The Big Bang Theory Season 3, Episode 5