If you just have one or two classes to introduce Halloween, you can teach some words of Hallween and do a simple introduction of Halloween, then do a fellow up activity. 

I designed three lesson plans for different grades. Here we go.

 First and second grade. 

As for lower grades, we use song to catch up Halloween words. Don't forget to dacne with TPR. Halloween ABC is a nice song for them to practice letter names and some Halloween words. First grade, they have to read the letter names with the meledy. Second grade, they have to sing the whole songs with action.  

 Lesson Plan for first and second grade 

 class one 

1. warm up 

Free talk about what do they do on Halloween? Kids usually did a lots of things in cram school or you can just show them the photo, ask them have you ever joined the party before. Then, why we have Halloween, let's see a video. 

Halloween Stories For Children  https://www.youtube.com/watch?v=F-TR35esdMA

2. presetation

Ask some questions like what do you see? when is Halloween? Do you notice about where is Halloween originated? 

3. practice

Let's learn more friends about Halloween. Let's see the video.  

Halloween ABC  https://www.youtube.com/watch?v=B7NjbznyCx8&feature=youtu.be&t=9

4. first time just listen. Senond time, just say the letter name. Third time, try your best to follow the song. Last, party time.

Teacher can invite a few students to come to the front to lead everydody to dance, don't forget to give them some candies.  

5.  warp up: pick up some words like vampire / bat / witch / spider 

teacher says a word, students have to say the letter name ( first grade) or the letter sound ( second grade)

if still have some time, you can sing the song again. 

 class two - ART CRAFE 

 Mask:

Teacher have to prepared printed worksheet and invited the kids to bring colored pens. 

warm up: review the Halloween ABC song and invite Ss to pick up a new friends to draw. ( Teacher can offer different choices.)

Presetation: write on different names on the board and ask Ss to write their friend's name on the worksheet. 

DIY TIME: give Ss 10 to 20 minutes to finish their work. When they finish, they can do 1. cut off the edge 2. paste it on the hard paper. 3. dig two hole on the mask and use to rubber bins to make a mask. 

Procuction: invite the students to introduce his / her new friend by using "This is my friend ____" / "SHE / HE / IT IS my friends _________ " 

Don't forget to give them a big hnad. 

 Miss Cain Pumpkin Face  http://cainx.pixnet.net/blog/post/310416767

it's easy to operate, too. Teacher has to prepare some colored papers (a student needs three) or  you can remind students to bring their own. Also, we need some glues or tapes. 

Warm up: review the Halloween ABC song and invite Ss to create a new monster and name it. 

Presetation: write on different possible names on the board and ask Ss to create a name of the monster. Then, write their friend's name on the monster's face.

DIY TIME: give Ss 10 to 20 minutes to finish their work. When they finish, they can do 1. DIY the eye, nose, mouth. 2. paste on the face

Procuction: invite the students to introduce his / her new friend by using "This is my friend ____" / "SHE / HE / IT IS my friends _________ " 

Don't forget to give them a big hnad. 

 more songs 

THE ITSY BITSY PUMPKIN  https://www.youtube.com/watch?v=0nDqK6V1cuU

Spooky Wheels on the Bus  https://www.youtube.com/watch?v=FX3Jkv3EUSc

 third and fourth grade 

As for third and fourth grade ​​​​​, you can use songs and picture books together. TPR is still nice but do remember to ask them to remember as many words as they can. 

  Lesson Plan for third and fourth grade 

 class one 

1. warm up 

Free talk about what do they do on Halloween? Kids usually did a lots of things in cram schools。 Or you can just show them the photo, ask them have you ever join the party before. Then, why we have Halloween, let's see a video. 

Halloween Stories For Children  https://www.youtube.com/watch?v=F-TR35esdMA

Ask some questions like what do you see? when is Halloween? Do you notice about where is Halloween originated?  what do we do on Halloween? Let's learn more candies and fruits. (  Apples, peaches, tangerines. Cookies, chocolate, jelly beans.   Lemons, grapefruits, limes so green  ) 

Trick Or Treat |  https://www.youtube.com/watch?v=kt319a0GkCc

First, Listen. Second and third time, try your best to follow. Then, ask some questions like what do you see? Tell me some green fruits. Tell me something sweet / sour. Tell me something good to eat. 

2. presetation: introduce a picture book 

(Go away big green monster )https://magic105.pixnet.net/blog/post/43904479

 class two - ART CRAFE Flying witch 

1. warm up : Sing the song together and talk about what is a witch look like

 Guess Who? | Halloween Songs  https://www.youtube.com/watch?v=0GhLMPytlcc&feature=youtu.be&t=8

2. Presetation:

 WITCH: each students will have an A4 black paper and half A4 size green / purple/ yellow paper. Teacher prepares some newspapers.  Teacher reminds students to bring their own colored pens. 

 sentence: She has ___face, ____hat, and _____ nose, and ____eyes. (Encourage students to draw and practice colors.)  

 SKELENTON: each students will have some cotton swabs and an A4 black paper and a half A4 size white paper. Teacher reminds students to bring their own glues. 

 sentence: He has ___bones, ____head, and _____ nose, and ____eyes. (Encourage students to draw and practice colors and numbers.)  

 more craft like black cat, ghost, bat

 in the dark dark house  https://magic105.pixnet.net/blog/post/45423792

  more Picture books 

I'M NOT SCARED!  https://www.youtube.com/watch?v=KtdMQpApp5Y

THERE WAS AN OLD LADY WHO SWALLOWED A BAT https://www.youtube.com/watch?v=fl3HZpQ9E-M

 fifth and sixth grade 

As for fifth and sixth grade, they need more challenges. They are familiar with Halloween so that you can challenge with different youtubes like fun facts of Halloween. 

 Lesson Plan for fifth and sixth grade 

 class one 

1. WARM UP: USE KANOOT to ask some questions or use ppt to demostrate questions. Then, teacher invites Ss to watch a video to show the answer. 

Halloween Facts for Kids  https://www.youtube.com/watch?v=p4mkO7038JY

2. presetation：talk about the fun fact of Halloween

1.)  Halloween is not about sacred, it's about fun. 

2. ) Over two billion dollars are spent on candies every year

3. ) Instread of carving pumpkins, people used to carved on turnips

4. ) thousands years ago, many cultures had festivals for changing seasons

5.) The earliest example of trick or treating is from Ancient Greece.

6. ) trick or treating become commom in 1920 in the US.

3. DIY: make a poster 

divide the class into groups and each group chooses a fact about Halloween. Start with, "Do you know .....?"

4. Production: 

each group takes turns to show their ideas and others to vote which one is the best.

5. Wrap up: awarding time 

choose: the best artist / the best idea / the best performance

 there is another halloween fun facts 

Halloween Fun Facts  https://www.youtube.com/watch?v=fDDEhoOxUkc

 class two: An Haunted House 

1. warm up: explain what they are going to do

divide the class into groups and each group has to make some origamis to form a Halloween Family. They have to paste their roles on the poster and use the sentences below to describe their family. 

"This is my family" / ___ is ________in the living room. ___ is ________in the kitchen. ___ is ________in the bedroom. ___ is ________in the bathroom. 

2. presentation: play a few videos 

3. DIY TIME 

 Halloween Origami  http://en.origami-club.com/halloween/index.html

 Halloween Origami youtube 

Pumpkin  https://www.youtube.com/watch?v=_k_xaI98JLw

Halloween Lights  https://www.youtube.com/watch?v=2lNIxJ9_s7I

Origami Ghost  https://www.youtube.com/watch?v=dR-NsyJ7IW0

 Origami Bat  https://www.youtube.com/watch?v=Swxn9hwzQWw

4. Production: 

each group takes turns to show their haunted house and others to vote which one is the best.

5. Wrap up: awarding time 

choose: the best artist / the best idea / the best performance