Idea: Elephant suit
Elephant suit should be a battlesuit that in addition to slightly more protection has a trunk and can suck liquids in itself and eject them later. It has two liquid containers that can be filled with different liquids.
Water = if eject on wallwalking aliens prevents them from wallwalking for 5 seconds
Lava = damages aliens and humans
Slime = sticks to aliens and humans and slowly damages them
Water + Lava = hot steam that damages aliens and humans without battlesuit
Water + Slime = sticky liquid that sticks to aliens and humans without armor or helmet damaging them for 10 seconds and reducing the friction between them and the floor making them slip and preventing them from wallwalking
Slime + Lava = poisonous steam that damages aliens and humans without helmet or battlesuit