Plapis stands for plasma pistol.
You can post your medal idea to the pinned thread https://www.halowaypoint.com/en-us/forums/29568daf8cd14083bd1b70a810bf3581/topics/what-new-medal-would-you-love-to-see-in-infinite/62595fdb-6a3e-45ed-835e-7e78ae80da52/posts at the top of this forum. Thanks!