im not sure if its auto hit, however, the easy way to check it would be to make a tab containing the pet combat log and you should see if it has tohit rolls or not in there
Shield Breaker is a good set to put in it (Acc DDB). Gives lots of defense, including melee, which is good for a toe-bombing trapper. You may not know this, but many melee PBAoE attacks are tagged as Melee_attack and NOT AOE_attack. So having both melee and AOE defense is essential to using trip mine in combat.
Acid mortar takes Accuracy enhancements and Accurate Defense Debuff sets. Detailed Info claims the acid splash has an accuracy of 1.00. This implies it can miss.
I have never, ever seen it miss. Ever. Even if it hits multiple targets, all get hit, always.
Am I just incredibly lucky? Or is it autohit?
If it's not autohit, how much accuracy do people usually slot into it?