Growing Spell for Getting Taller Quickly

Witch Hat 2 (Medium)

Mix week-old porridge with mushy peas,
crumble in some mouldy cheese.
Add six nettles picked at night,
a unicorn eyelash for extra height,
a trail of slime from a yellow snail,
add a spider's web, and this can't fail.
Now eat it fast and stretch up tall -
You'll soon be higher than them all!