Hammer of Tellus Actions

Equipping the Hammer provides the following abilities

Recieve some Pushback. If this weapon makes a critical hit on an attack action, and the target fails a check against the ability used for this attack, they can be pushed up to 10ft in a direction of your choosing. This effect is applied before any other conditions this weapon might apply, such as the prone condition.

I've Fallen and I Can't Get Up. If the polearm is within reach of a prone enemy, a heavy downward strike can be performed as a bonus action. The weapon’s damage die for this attack is a d12, and it deals bludgeoning damage.
For enemies that are 10ft away, this attack is performed at Advantage. For enemies that are 5ft away this attack is performed at Disadvantage.
On a hit with this attack, the target must make a CON saving throw, or be stunned for a turn, and take additional thunder damage equal to the ability used for this attack. Enemies who are wearing metal armour make this CON throw with Disadvantage.

Mined the Gap. If the polearm is within 5ft of a prone enemy, they can be stabbed with the spear at the end of the polearm, as a bonus action. The weapon’s damage die for this attack is a d8, it deals piercing damage, and the attack is made with Advantage.
If the target is wearing metal armour, they take additional psychic damage equal to your proficiency bonus, as they suddenly realise the weapon gives you the ability to accurately stab them through the gaps in their armour.
If this attack is a critical hit, and the target fails a DEX saving throw, the ability to stab at the joints and gaps in armour also causes a limb of the enemy to be disabled. This occurs only if the enemy has limbs, and they do not need to be wearing armour to be affected (the ability to accurately target parts of armour translates to the ability to accurately disable a limb). Whether this effect occurs, the severity, and which limb is disabled is at the DM's discretion.