Timed Trap tiles (I don't have a better name)

Akoni

We have Countdown tiles and we have Trap tiles. I think they should get together and have a baby? A Timed Trap tile. It will behave and be treated like a Trap tile to your opponent while also behaving and looking [somewhat] like a Countdown tile for the player. It's appearance on screen would be that of a Trap tile with a counter in the center that counts down each turn like a Countdown tile. It would continue to be invisible to the enemy unless otherwise stated.

This would open up various avenues such as requiring the opponent to play hide and seek in an effort to find the tile before it goes off. This would also allow the development of more powerful or impactful Traps by allowing devs to put a limit on how long the Trap can be present. For example, Trap tiles generally aren't selected, but randomly placed. Allowing players to select which tile becomes a Trap makes that Trap very dangerous, but the timer would limit its existence. 

Additionally, there may be a desire to give Countdown tiles a better chance of surviving outside of fortification. In this case, a Timed Trap tile is basically an invisible Countdown tile. This is beneficial for powers that don't have a massive impact, but would lead to angst over spending AP for the chance at a lackluster effect only to have that tile matched away or destroyed. Weaker powers can utilize these "invisible Countdown tiles" to increase the likelihood of success.