This form is Acrostic. It spells out something diagonally on the left side of each line. This form is a bit of a challenge to create in a rhyming poem. More of a challenge is a Double Acrostic, where in addition to left side is the spelling out on the right side in sequence after the left side. Haven't tried this yet. But here an Acrostic Poem for the season.
Horror has become the theme
A night that now is a fright
People dress to the extreme
Putting on a look to excite
Your senses break out in a scream
Humor in fright the theme this night
Aiming towards a treat the scheme
Looking a fright one just might
Locating your flashlight as a beam
Onto the house that's lit bright
Where the decorations reign supreme
Electing to venture out this night
Eerie, thou how Halloween may seem
Now happy with your treats, it's a delight
To All A Happy Halloween--Be Safe!