What does starting a boss fight do?

[peteed1985]

So I die easily while in hell even if i'm in full molten gear and really nice weapons just to the random spawning enemies because theres just so many and they never stop spawning so i'm kinda worried theres no way to kill Wall of Flesh because i'll have him and the other enemies to deal with all at once.

Thing is i've never really thought of it until now but when I am fighting the Eye of Cthulu or the Eater of Worlds I don't think i've seen another enemy around so that begs the question does summoning a boss delete all other enemies from the map until fights over or what?

 

[Shika]

There is an enemy limit, and many times, a single boss will count as multiple enemies, therefore taking up multiple of those spaces. I'm not sure if the spawn rate decreases or not, though. Normal enemies still can spawn, usually, though, I believe. My, what an abundance of commas...

 

[Pixel]

No, it doesn't. At least I think so.

 

[MiltVala]

Try using more punctuation buddy
Supposingly, bosses will count toward the spawn rate making other mobs spawn less. If you are really having that much trouble with other mobs, try using a calming potion (made from damselfish from sky islands and daybloom)

 

[ExoticCharm]

http://terraria.wiki.gg/Spawn_Rate#Spawn_Rates

Simply put, each biome in the game has a max spawn number. Different enemies count for different amounts, so it's not as simple as 1-to-1. Most (if not all) bosses count as something high enough that normal monsters can't spawn. It should be noted that the battle potion doubles the max spawn number and might allow some enemies to join a boss fight, however the maximum of the max spawn number is 15 and many biomes have numbers close to this already.

The bottom line is that normal enemies shouldn't be getting in your way very much during boss fights.

 

[FlakMaster]

In most boss fights you shouldn't see a single enemy. There are the rare cases when you do see one. However, the enemies that are still lurking around after the summon will still be there until they decide to despawn or get killed.

One thing to note though, is that if you have the battle/water candle buff active, enemies will definitely spawn mid-fight with a boss. I've done a few runs where I have the Battle Potion and Water Candle buff on permanent and it can sometimes be troublesome.