I'd call it "teasing" or "play" rather than "trolling". Trolling has a bit of a mean connotation to it where as teasing/play is more, well, playful.

But, yes, after a certain point babies/infants do understand teasing play. That's essentially what games like peek-a-boo are. Babies don't have real object permanence until they're 8-12 months. That is, they don't fully have the ability to recognize that a thing still exists when it is not within their site/sensory perception until they're 8-12 months. (It gradually develops, so they'll gain more and more object permanence as they get older rather than just turning on all of a sudden.) When you play peek-a-boo, you're using this lack of fully developed object permanence to tease them. They won't recognize it as teasing at first, but they get it pretty quickly. That's why they laugh and have fun with it.

Yeah, with time they get more and more cheeky. Depending on how you raised them of course. A common occurrence is a toddler offering you something and then pulling away when you reach for it and dying of laughter.

What do you mean by "trolling"? It's not like that's a word that has a consistently agreed-upon definition.

I get screamed at for attention sometimes, which seems like a pretty good definition of trolling. So yeah.

Define trolling. Joking or messing with someone? Totally.

Kids love laughing. Comedy is all about subterfuge and up-ending expectations. "Trolling" is the same. Kids make up the worst unfunny jokes as they don't understand what makes a joke funny instead of ridiculous, but they do understand the art of the unexpected.