Nyarlathotep
Explorer
I think it EBT does do lethal damage (and so does constrict). My default assumption is that whenever damage is mentioned it's considered to be lethal damage of a specified type unless the text mentions otherwise. In this case:
According to the glossary on the WotC site, deal damage is defined as:
and damage is defined as:
I suppose you can read it a couple of ways, but to me this means that there is: Lethal damage, non-lethal damage, and ability damage. Bludgeoning is specifically mentioned as a type of weapon damage. and non-lethal damage isn't specifically mentioned in the spell description. So the character takes 1d6+4 weapon damage of the bludgeoning type. If the characters was to have taken non-lethal damage it would be specifically mentioned as such in the spell description.
SRD said:Black Tentacles
Once the tentacles grapple an opponent, they may make a grapple check each round on your turn to deal 1d6+4 points of bludgeoning damage. The tentacles continue to crush the opponent until the spell ends or the opponent escapes.
According to the glossary on the WotC site, deal damage is defined as:
Glossary said:<b>Deal Damage</B>
Cause damage to a target with a successful attack...
and damage is defined as:
Glossary said:<B>Damage</B>
A decrease in hit points, an ability score, or other aspects of a character caused by an injury, illness, or magical effect. The three main categories of damage are lethal damage, nonlethal damage, and ability damage. In addition, wherever it is relevant, the type of damage an attack deals is specified, since natural abilities, magic items, or spell effects may grant immunity to certain types of damage. Damage types include weapon damage (subdivided into bludgeoning, slashing, and piercing) and energy damage (positive, negative, acid, cold, electricity, fire, and sonic). Modifiers to melee damage rolls apply to both subcategories of weapon damage (melee and unarmed). Some modifiers apply to both weapon and spell damage, but only if so stated. Damage points are deducted from whatever character attribute has been harmed -- lethal and nonlethal damage from current hit points, and ability damage from the relevant ability score).
I suppose you can read it a couple of ways, but to me this means that there is: Lethal damage, non-lethal damage, and ability damage. Bludgeoning is specifically mentioned as a type of weapon damage. and non-lethal damage isn't specifically mentioned in the spell description. So the character takes 1d6+4 weapon damage of the bludgeoning type. If the characters was to have taken non-lethal damage it would be specifically mentioned as such in the spell description.