A troll is someone who posts something ridiculous online to get a reaction.
Trolling is the verb for doing this. (Convergent words).
But when people say, "Don't feed trolls," (as in, don't respond to that idiot on the message board), they say so with an image of a monster under a bridge, while when they say, "Don't troll," (as in, don't be an idiot and put inflammatory prompts on the message board), they say so with an image of fishing using long lines off the back of a boat. (Divergent images).
Which came first? Trolling before trolls, surely. And then "Don't feed trolls" was a funny leap off the back of the ship to under the bridge. It makes me furrow my eyebrows.
The words come from totally different places, too.
The verb troll comes from Old French troller, a hunting term.
The noun troll comes from Old Norse for a mythological monster.