 When an Illithid undergoes ceremorphosis, it can occasionally take on some elements of the absorbed host creature's former mind, such as mannerisms.This typically manifests as a minor personality feature, such as a nervous habit or reaction (e.g., nail-biting or tapping one's foot), although the process that determines the type and number of traits so inherited appears to be stochastic.Some adult Illithids have even been known to hum a tune that its host knew in life.