Got a newbie question…I played in the Crucible last night with a Arcanist-Demolitionist, and he used a skill I really liked but I don’t know what it was…it placed 3 mortar tubes on the ground that fired shells upward and fell down. Can someone please tell me what it was?
mortar traps 
Mortar Trap, bottom line on the right of the Demo’s skills.
Thanks, folks! Be safe!
Hm, probably is Thermite mines as malawiglenn said. I don’t recall them firing upwards, but I’ve never used them much. I know you can get items in the game that increase the number of Mortar Traps you can have.
It can be thermite mines too yes, since they squirt upwards.
Shells though sound more like Mortars.