Read kindergartners a story based on a monster character, then use the story to test students' reading comprehension skills. Ask questions after the reading of the story, like what the monster's name was, what his physical traits were and what his main issue in the story was.
You can turn a math lesson into a monster of a good time using some clip art you've found on the computer. Visit a site with free clip art to find some cute monster faces to print out. Paste the monster faces onto Popsicle sticks and use them to make addition and subtraction problems, asking students how many monsters there are as you add and remove each monster.
Create a writing exercise centered on a monster theme, which gives kindergartners a chance to flex their creative writing skills. Ask students to write a story about an imaginary monster, giving their monster a name, a home and a personal monster trait. You can grade the papers as though they were essays.
Make a monster-themed craft for art class, turning the elective period into a fun and spooky time for kindergartners. Give students craft paper, pipe cleaner, scissors, glue and googly eyes and let them come up with the funniest and silliest monster they can think of.