Invisible Encounters (ACE)

Working on a survival horror RPG. Part of this design is that I am going to emphasize unique monster encounters. One of the creatures I am working on begins the encounter completely invisible with a high evasion rate. Upon striking the enemy down to 80%hp, the enemy becomes visible. This is fine by itself, but there is a bit of a giveaway that the enemy is there by two facts;

1. The encounter itself exists.

2. Even though the enemy is invisible, you can still target and strike the enemy.

So I have a user experience question. Would those two indicators be too much of a dead giveaway to ruin the idea/experience? I can change the name of the enemy from something like "???" while it's invisible and then once it's visible, change the enemy name to an actual name.

Thoughts?

If it's invisible, and I can't target it, nor does it appear on the list, I'm going to think there's a bug in the game.

??? would be better, but then again if I can't target it and I'm just sitting there tanking hits...

Heh, I get a bit of nostalgia from the "Ghost..." in Pokemon Blue.

I've got it worked out to the following;

1. Encounter is invisible in the battle screen.

2. Name text is "???".

3. Enemy has high evasion rate while invisble.

4. At 80% remaining, the enemy becomes visible (via the transform tool).

5. When visible the name changes.