All platformers need to have trap plates of some sorts! So this is what I've created for my sub! All it does is fades out and becomes passable, so player (or other npcs) will fall through it to their death. Logic is quite simple, I activate them with a short raycast that I projects from entities origin downwards to an extend that raycast's 'end' position is slightly poking from entitie's lower bbox edge. On activation it has 3 states. Activation (when it fades out), counter (5 seconds) and fade back in state.

You can see how it all looks here: