Hellbat

	Classic	Expert	Master	Legendary (For the Worthy)
Life	46	92	138	184
Attack	35	70	105	186
Defense	8	8	8	8
Knockback Taken	80% (High)	72% (Med)	64% (Med)	64% (Med)
Coins	120	3	3	420

The last column is Master mode in a world made with the For the Worthy seed. Its numbers were measured in the game, not computed here.

For one player in a world before Hardmode. Expert and Master scale life, attack, knockback and coins by the game's own multipliers.

Coins: each kill rolls the coins from 80% to 175% of this value, then rarer extra rolls can add more.

In a Hardmode world

On Expert and Master, a Hardmode world raises weak enemies: when attack plus defense plus a quarter of life is under 80 (100 after Plantera), the game multiplies them up.

	Life	Attack	Defense	Knockback Taken	Coins
Expert, In Hardmode	100	62	8	72% (Med)	240
Master, In Hardmode	150	93	8	64% (Med)	240
Expert, After Plantera	100	62	8	72% (Med)	240
Master, After Plantera	150	93	8	64% (Med)	240

Classic

Item	Quantity	Chance	Kills for 50%	Kills for 90%	Conditions
Bat Bat	1	1/100 (1%)	69	230	In a world made with The Constant seed
Magma Stone	1	1/150 (0.67%)	104	345
Bat Bat	1	1/300 (0.33%)	208	690	Not in a world made with The Constant seed

Expert

Item	Quantity	Chance	Kills for 50%	Kills for 90%	Conditions
Bat Bat	1	1/100 (1%)	69	230	In a world made with The Constant seed
Magma Stone	1	1/150 (0.67%)	104	345
Bat Bat	1	1/300 (0.33%)	208	690	Not in a world made with The Constant seed

Master

Item	Quantity	Chance	Kills for 50%	Kills for 90%	Conditions
Bat Bat	1	1/100 (1%)	69	230	In a world made with The Constant seed
Magma Stone	1	1/150 (0.67%)	104	345
Bat Bat	1	1/300 (0.33%)	208	690	Not in a world made with The Constant seed

Chance is per kill. Kills for 50% and 90% is how many kills give that chance to see the item at least once.