Black Widow: Recharged

This can be done in Arcade or Challenge mode, but just as with a few other trophies, Challenge #6 "Mass Extermination" is a good place to get this. You're required to kill 45 Hornets, but if you let them lay an egg or two, the egg/s will hatch into a Grenade bug. If you shoot the Grenade bug, it'll explode and kill everything (including you so be careful) close to it. This challenge has a LOT of enemies flying around so it shouldn't take too long to get at least 5 near the Grenade bug to kill them. Once 5 are killed, the trophy will unlock.

This trophy does unlock in the video provided under After All , so if you need a visual reference, please see Challenge #6 in that video.