Get part standing on. ( raycasting) help?

I was wondering if there was a way to raycast the part directly under the players character ( using head as x,y axis),

I tried to use the raycasting tutorial as a basis ( ray = game.players.localplayer.character.head.position, vector3.new(0,-5,0) ( errors because I just wrote this example for the thread)

but It wouldnt work, it would shoot a few feet infront of the player or something like that. I was wondering if anyone could help me :)