|Location||Anywhere with Tchortling Sowers|
Immunity to debuffs and other status effects
Tentacles have both melee and ranged attacks. The melee attack deals 30-40 Mechanical damage, and will be used exclusively as long as the player is within melee range. Their ranged attack on the other hand deals 35-70 Bio damage, and has a range of 10.
It is preferable to deal with tumors before they could grow into tentacles, but once the damage is done the best strategy depends on their numbers. Tentacles don't have much health, but it's more than enough to make killing a large number of them within a single turn very hard. They don't have many resistances, but are immune to every debuff and status effect under the sun.
Depending on your resistances and defense skills, you might want to stay in melee range to avoid the higher bio damage.
Tentacles, lacking a brain, are immune to Thought Control abilities.
It is not possible to set tiles with tentacles on fire. However it is possible for tentacles to grow on tiles which already are. In this case they will take damage from the fire normally.
While area attacks, especially higher tier grenades, are good for dealing with tentacles, keep in mind that Cryokinetic Orb will never hit them.
Thanks to their True-Sight, it is impossible to sneak past tentacles. However if you are not surrounded, moving out of their range is the best possible strategy, since tentacles have an extremely short lifespan and will naturally die after only 3 turns.