Would it be possible to have a Mole in the game? (As in a real mole that burrows underground…)
Character profile: Advantages.
It can burrow, undetected, underground.
If it gets under your character, it can rise up and attack you!
It can burrow under buildings and in time undermine the foundations causing the building to collapse!
Character profile: Limitations.
When above or below ground, it can only move slowly.
It takes quite sometime to undermine the foundations of a building. Whilst the building is being attacked, it will rock slightly at regular intervals. (As a warning to the owner that his/her property is threatened.)
If it surfaces too far away from a character, it can not “see” them, so can not attack.
It can not cross water, under lava or very rocky ground.
Character profile: Threats.
Engineers can plant mole traps that only they can see. If the mole moves close to the trap is will be sprung and the mole is killed. (The trap would display that it had been sprung.) Collected dead moles can be sold for moleskin or made into armour.
To counter the mole attacking a building, a character can have a ferret. When it is noticed that the building is rocking, the ferret has to be instructed to dig the mole out. A ferret can also be used to attack a mole above ground but wont know were they are when the moles is burrowing across the playing field.