Zig Zagged: The PSI Bug latches onto you, and then jumps off to launch a powerful ranged attack, then rushes you again, then does the same attack at point blank range, then jumps off...
Averted: Enemies are all armed and never get within close range.
Enforced: "This game needs to be scarier. Let's add an enemy that grabs onto the player out of nowhere that they need to shake off!"
Lampshaded: "Gah! Why are all the enemies here so... clingy?!"
Invoked: A character tricks a pursuing enemy into going through a PSI Bug nest, in the hopes they'll slow his pursuer down.
Exploited: A hungry character shoves an animal carcass into a PSI Bug nest, then harvests all the PSI Bugs clinging to it for extra food.
Defied: A character sprays himself with repellant before entering the bug-infested forest.
Discussed: "Ugh, I hate forests like this.... They're always full of tiny little things that grab on and don't let go!"
Conversed: "Man, those PSI Bugs cling onto everything! You'd think someone would've made a bug spray for them or something."
Deconstructed: The area PSI Bugs are from looks almost plague-riddled: all the animals, buildings, plants, and people have PSI Bugs on them. They're too ubiquitous to deal with - swat one off, and more just show up to take its place - so people have to ignore them as best they can. Meanwhile, almost everything is dying because of the drain all these parasites put on them.
Reconstructed: People have developed pesticides and repellant sprays to drive PSI Bugs away from civilized areas. Some lone hero trekking through the wilderness could still run into some, though..
Played For Laughs: As the party emerges from a thicket, the Plucky Comic Relief character is covered with PSI Bugs... and doesn't notice until his teammates mention it.
Played For Drama:
PSI Bugs are a serious health threat: not only do they inflict injury, they're almost impossible to get off and can transmit serious diseases.