Help, to when I fall I deal damage in mobs around of me.

Hi, I'm making a Mod with elements from the MCPVP like HG, and I need help to creator a Stomper, that's a kit does the Player when fallen from high places killing player or mobs around of me.

but I'm new in Mcreator and I'm guiding of forums. 

If somebody knows to do this or something as this, please help me with images lmao.

(My english is basic :P)