You can use Google Draw to create your own cartoon strip.
Use the Insert menu to look for backgrounds, and then crop them into perfect squares. The alignment indicators will help you line everything up.
Use the Insert menu to find some characters, and select PNG for characters without a background.
Use the shapes tools to find speech bubbles, thought bubbles, etc.
When Sharing a Google Project, you'll want to do 2 things.
Go to the File menu and select Publish to the Web. When the dialog box pops up, click on the Publish button. You'll be asked if you're sure you want to publish this selection - just click OK. Once you do that, you'll have an opportunity to copy the link. The link will go to your project in presentation mode so it'll look good and navigate correctly. Use that link as a way to show your project to others. (email it to someone, add it to a discussion post, put it in a Doc or Spreadsheet, add it to a Google Form...)
Use the Share button in the upper right-hand corner of the screen, and type your teacher's name into the box provided. This will allow your teacher to collaborate with you and give you feedback.