Smaragdine Golem 2014

The smaragdine golem makes two Slam attacks. It can replace one attack with a use of Release Spell.

Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage plus 22 (5d8) force damage.

The smaragdine golem releases an absorbed spell's energy in a green burst centered on a point the golem can see within 60 feet of it. Each creature, other than the smaragdine golem, within 5 feet of that point per level of the absorbed spell must make a DC 18 Dexterity saving throw. On a failure, a creature takes 10 (3d6) force damage per level of the absorbed spell and is incapacitated until the end of its next turn. On a success, a creature takes half the damage and isn't incapacitated. The golem can use this action only if it is Charged (see the Magic Vessel trait).

When a creature the smaragdine golem can see within 30 feet of it casts a spell, the golem can absorb the spell's energy, countering it. This works like the counterspell spell, except the golem must always make a spellcasting ability check, no matter the spell's level. Alternatively, when a creature the golem can see within 30 feet of the golem starts its turn while under the effects of a spell, such as bless or heroes' feast, the golem can absorb the spell's magic, ending the effect. In either case, the golem's ability check for this is +10. If it successfully counters or ends the spell, it becomes Charged (see the Magic Vessel trait). The golem can't use Absorb Spell while it is Charged.