Whenever Abigail goes to attack, she will stop in place and try to attack as normal, but she won't deal damage sometimes, especially if the enemy is stationary. My best guess is that she is stopping to attack a bit too far away from the enemy.
Golden Heretic Snakeboat
Wall of Flesh
No, she is supposed to have an area of effect damage attack, but it's bugged so the aoe doesn't deal any damage, essentially making Abigail useless
