Chain Lynx

Immutable Form. The Chain Lynx is immune to any spell or effect that would alter it's form.

Magic Resistance. The Chain Lynx has advantage on saving throws against spells and other magical effects.

Magic Machinery. The Chain Lynx's weapon attacks are magical for the sake of overcoming resistances.

Overheating. Dealing 20 or more fire damage between Chain Lynx's turns causes it to overheat. When overheated, the Chain Lynx exposes it's core until the end of the machine's next turn.

Multiattack. The Chain Lynx makes two attacks chosen from: claws, tail, or spikes.

Claws. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 21 (3d10+4) slashing damage. 

Grenade Launch. The Chain Lynx spits a grenade that explodes at a point it can see within 60 feet of it. Each creature in a 20-foot radius sphere centered on that point must make a DC 18 Dexterity saving throw. A creature takes 25 (8d6) fire damage on a failed save or half as much on a successful one.

Spikes. RangedWeapon Attack: +6 to hit, range 30/120 ft., one target. Hit: 9 (2d6+2) piercing damage.

Tail. Melee Weapon Attack: +8 to hit, reach 10 ft., one target. Hit: 17 (3d8+4) piercing damage, or 32 (6d8+4) damage if the target is prone. Additionally, the target must succeed on an opposed Athletics check or become grappled by the Chain Lynx's tail. The Chain Lynx cannot use it's tail attack while grappling a combatant.