Alright here we go, the first thing u need to do is find your static mesh you want to do the killing. This can be anything from a big cube to a giant stuffed teddy bear.
1) select your static mesh in the content browser(generic browser if your in ue3)
2) place your static mesh in your map.
3) right click the mesh and choose "replace with > interpactor"your static mesh name here"
4) open kismet and right click the screen. Select new event > level loadup
5) create a new matinee sequence.
6) click the matinee and create a new empty group, and then new movement track.
7) create your animation(if you dont know how to do this leave a comment) this animation should be your object moving to cause pain or death. I.E a falling spike a crushing wall, ect.
8) close matinee and right click on the kismet screen, select new action > misc > delay
9) Right click the screen and select new variable > float > random float
10) set a max and min value, this will determine how long before your animation plays again.
11)plug completed from the matinee into start of the delay
12) plug finished from the delay into play of the matinee this will loop your animation with a random delay in between.
13) now to make the animation do damage, right click on a blank spot in kismet and select new event > physics > mover. delete the matinee that comes with this.
14) select your interpActor in the editor window if it isnt selected already, and then right click the mover event and select "assign interpActor..."(if you have multiple actors make sure you select the right one)
15)now right click anywhere and choose new action > new actor > modify health, and set how much damage you want to be done when the player is struck.
16) right click modify health in the box where it says "target" and select create new obj variable.
17) now plug in hit actor of the mover to the in of the health modifier, and plug actor hit into the new obj variable we just made.
18) finally click your matinee and in the properties scroll down and click rewind on play. Also make sure you have connected your matinee with the level loadup we made.
Alright your done, your should now have your very own crushing block, falling spike, or whatever you did. if you have any problems or think i left something out drop off a comment, and i'll do my best to help you, and fix up the tutorial. After all this is my first tutorial give me a break :)