They can be very dangerous as they can frequently spawn in very large numbers, particularly within the tunnels that run underneath The Crimson. Ranged or magic weapons work much better than most melee weapons against them.
It should also be noted that as long as they are climbing on background walls, they are much less vulnerable to knockback. Due to this, it's inadvisable to take on more than one in melee combat simultaneously. This is because they can easily flank the player when more than one Blood Crawler attacks at a time.
While the Blood Crawler is crawling along background walls, it appears to act like many flying enemies, in that it will rebound from Wood Platforms when it's moving downwards. This can be used to the player's advantage, both whilst fighting and attempting to escape from swarms of them. Placing a row or just a few wooden platforms as one descends can quickly cause Blood Crawlers' speed to be significantly reduced, and clever placement of platforms can even halt them completely.
It is possible to farm Blood Crawlers. However, they may have difficulty in reaching the player if she/he is standing on an outcropping, requiring the player to move back and forth across the pit in which the Blood Crawlers are spawning. They have a slow spawn rate when the player is nearby, so the farming may take a while. It is recommended to have a broadsword.
- Despite the fact that Blood Crawlers don't have a spine, as they are arachnids, they drop vertebrae when killed.
- Added to the game.