How to hide part of object when going through floor

Hi, I currently have a spike obstruction that moves up and down through the floor, so the player only has certain time periods that it can move from one part of the level to the next. The issue is, as the spikes (cones) move down through the floor, they are easily visible by the player since they're just below the actual floor. Is there a way for me to hide the part that goes through the floor as it goes down? Thanks.