...As all the posters mysteriously disappeared, the shrapnel all fly around the globe, then crash into each other. However, one piece was a bit ahead of the other shrapnel, and it continues flying to hit me!

But I duck, and if flies over my head to hit the next poster.

I ball up the shrapnel with my magic and dunk it on the next poster

I pull out a portal, literal black hole style, and close it, shutting the shrapnel in the realm of oblivion, thereby cancelling its existence.

I then open a new portal, this time to a vacuum dimension, and suck everything in front of me in, including the next poster!

I stick a comically large and unrealistic toilet plunger onto the wall so as to not be sucked in.

I take out a flashlight and blind the next poster.

Good thing I'm wearing sunglasses!

I close my vacuum portal and open a new portal. This time, it leads to a dimension of purely water, and I send a small tsunami towards the next poster!

Using the convient power of plot armor, I withstand the assault long enough to send a main character to attack the next poster

But then the main character has a psychological crisis in which they become a villain and attack everyone! I hide inside a convenient plothole, after closing the water-portal

I use my powers as a realized Sylph of Heart to mediate the characters' internal conflicts! They go home!

I jump up and swing a quarterstaff at the next poster!

I summon a level 10 Monk (Good) from the realm of Dungeons and Dragons, who blocks the strike, then counter attacks!

My reflexes aren't fast enough, but I can roll with the hit and create distance for a shruiken throw!

The monk, being from another realm, has disappeared, to return from whence he came.

Instead, I dive behind some rubble from the previous battles and telekinetically fling a pebble at the next poster at the speed of a bullet!