A tentacle was a body appendage.
Kroll was mutated after it consumed a segment of the Key to Time. It grew until it was a mile across and a hundred forty feet high, with over thirty tentacles on each side of its body. (TV: The Power of Kroll)
The Masters of Dorada used to be humanoid, but over many generations their bodies became giant brains while their limbs became four tentacles. They could generate electric charges through these tentacles. (PROSE: The Dream Masters)