A [Hydroid] build for those who don't want to use orokin reactors or forma. Get yourselves some corrupted mods and [Pilfering Swarm] and you got yourself an efficient farmer.

Even if he has low duration the tentacles stay for a while after the timer ends, but do still spam it every 6-7 seconds (this is why efficiency is important). [Energy Siphon] and Zenurik school is not needed but highly recommended since it could stop you from ever running out of energy, for max farming take a [Nekros] with a desecrate build with you.

If you prefer to kill them yourselves and only use the tentacles for extra loot, you could switch out power strength for either more duration or survivability.