Frysling
Frysling has 100 health.
It takes extra damage from frost; fire, poison and spirit do nothing to it at all. Blunt, slash and pierce land at full damage, so that is what to bring.
Its only attack is snowball attack, 100 frost and 50 blunt.
Some of what it throws is elemental, so frost resistance is worth having.
Of everything craftable, 
Frostfire Crossbow, 
Frostfire Sledge and 
Thunderblood Crossbow put the most damage through what it resists.
It always drops 
Frostcore.
Frysling is a creature with 100 health that is immune to fire, poison and spirit, and weak to frost. Fire does nothing to it, which takes most of the late-game kit off the table, and frost weapons are the counter. Every kill drops exactly one Frostcore at 100 percent with no other loot and no trophy, making it the only creature in the game that drops the material. It walks at 5 meters per second and runs at 6.
Before 1.0 the only frostcores in a world were the ones hanging in mountain frost caves, which made them a fixed and finite supply per world. Fryslings are a renewable one, and they are trivial to kill at 100 health as long as you do not try to freeze them. Their snowball is 50 blunt and 100 frost, more cold damage than anything else their size throws, so frost resistance mead is worth having if a group of them finds you.
With devcommands enabled, this spawns Frysling in front of you. The third number is the level: 3 spawns a 2-star.
Creature ID: Frysling · all console commands and IDs