Don't won't to spoil it for everyone so the Davey Jones afect is explained below. Skip if you don't want to see.
As you enter the tunnel that is all dark where the voice would say "dead men tell no tales" they put a fog machine to make a screen to project a image on. Like how they do the rats on the indy ride. Davey Jones is projected on the smoke with a water effect so the smoke looks like water. His face apears from the water and says something then his face dissapears into the water. Forgot what he said though.