“it’s” always means either “it is” or “it has”.
“its” implies possession.
In general, apostrophe is used for:
- Contractions (don’t, won’t, she’s)
- Possession (John’s book, the dog’s bone)
- Plural possession (dogs’ bones, teachers’ lounge)
Never use apostrophes for regular plurals (he has so many pencil’s)
Missed ‘pain full’ opportunity aside, the last two panels ruin it. If you’re going to do shitty puns, do them with pride.