Penal Legion Squad?
Outflanking troops choice to take/contest objectives on the far side of the board.
A bit random with their abilities but i've found all of them useful, even assault 2 lasguns when you roll the wrong board edge.
They're a stubborn
Ld 8 roadblock if you need to throw someone under a bus for a turn as well.
The cheaty option though is only 65pts.
Guardsman Marbo
Appears anywhere on the board. Kills a squad with his demo charge then is a threat to anything else nearby with 6 attacks 2+ to wound or melta bombs.
I will always find the space for him in a guard army, as he really only costs an elite choice which you most likely wouldn't be using anyway.
When you wish upon a star, your dreams can come true.
Unless it's a meteorite falling to Earth, which will destroy all life, then you're pretty much hosed no matter what you wish for.
Unless it's death by meteorite.