This question, Are boggarts able to take the form of abstract fears? mentions that Boggarts are stated to be able to "take the shape of whatever it thinks will frighten us most."
We know that a Boggart would represent a fear of death via the viewer's dead body...
But how about a fear of drowning (as opposed to fear of death by drowning which could be easily represented by a drowned dead body)?
Would it be possible for the Boggart turn into a giant body of water that really engulfs the victim, so that the victim really experiences the state of drowning in 'real time'? Or would it be limited to showing the victim a 'copy' of their body struggling/drowning in a body of water?
What about a fear of being buried alive? Could it turn into a coffin around the actual body of victim; or would it be limited to showing a coffin (with someone thumping it from the inside)? Or falling from a great height? Or being stuck blind, dumb, deaf and paralyzed?
All these are things where the terror comes internally from the sensations which the situation makes the victim feel - watching a body drown or fall or be unable to move or watch a coffin from the outside, would be uncomfortable - but it would hardly engender terror the way seeing a giant spider in front of their face would terrorize someone deathly afraid of giant spiders.
Do we have any information (or calculated speculation) on what might happen in case a Boggart faces one with such types of fears?