From Halopedia, the Halo wiki
Once in Halo Reach a grunt tried to throw a plasma grenade at me but dropped it behind himself and when it blew up and killed him I got the points for it. >:)
Once in Halo 4 on the campaign (Composer is the name I think) I was in the space station and I hid behind the composer for cover from the banshees firing at me and got my mantis stuck under the Composer. I didn't do any mods or anything like that. I just some how randomly got stuck.
I like trains. (train hits me)