How does a bat have +0 modifier to attack?

I am quite new to playing DND and I'm struggling to understand how a bat has +0 to attack. I'm clearly missing something, but as per my calculations:

A bat has a strength of 2 (-4 Modifier). This is countered by a +2 of proficiency.

Looking at the bite attack (emphasis mine):

Bite. Melee Weapon Attack: +0 to hit, reach 5 ft., one creature. Hit: (1d1) piercing damage.

How is this calculated to +0? Should this not be -2?

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– Sdjz
Jan 17 '19 at 11:26
• Could you clarify what you mean by " This is countered by a +2 of proficiency"? I know this question is now answered, but it seems to me that a bat's proficiency is not knowable from its stats (since it doesn't seem to be proficient in any skills or saving throws). Jan 17 '19 at 17:43
• @Gandalfmeansme: There's a table of "Proficiency Bonus by Challenge Rating" in the intro to the Monster Manual and the corresponding section of the basic rules: dndbeyond.com/compendium/rules/basic-rules/…
– V2Blast
Jan 17 '19 at 22:29

I don't think there is a formula that will give us that +0.

The bat is a very weak creature, with a CR 0. Most likely, the D&D designers just didn't want him to have a negative attack modifier, so they set it at 0, despite having -4 STR and +2 DEX.

• If the attack was strength-based, the bat would need a +4 Proficiency (a bit high for a CR0 creature).
• If it were Dexterity-based, the bat would have -2 Proficiency (negative proficiency?).

It was a balance decision. The bat also does 1-damage with that attack, which is not derived from any formula. An unarmed strike is usually 1+STR, and a natural attack 1d4+STR, so both would deal non-positive damage.

From the DMG, on Creating Monsters (credit to Sdjz):

You can start with the monster's expected Challenge Rating table to determine an appropriate attack bonus for all the monster's attacks, regardless of its ability scores. [...] Feel free to adjust the attack bonus as you see fit to match whatever concept you have in mind.

Also, AFAIK, there aren't monsters with negative attack modifiers, are there?

• Comments are not for extended discussion; this conversation has been moved to chat. Jan 18 '19 at 0:55