NEW YORK – A study revealed that certain sea slugs discard their penises after sex and then they grow a new one.
A witness saw the copulation between sea slugs and said: ‘We propose that the tissue at the spiral part of the penis is compressed and undifferentiated, gradually differentiating into the next penis. It may need approximately a day for the spiral structure to be ready for copulation. No other animal is known to repeatedly copulate using such disposable penes.’
SOURCE: metro.co.uk