The Baby Troll is an episode of David the Gnome. It first aired 25 March 1985, and first aired in the US on 23 May 1987.
Lisa explains about the clothes gnomes wear. She mentions that David is out helping two deer who have their antlers locked together. David has to saw through the antlers to break them apart. When he is heading home, he sees a baby troll on a rock in the middle of the river! David decides to save the baby, although trolls are their enemies. David calls a gnome friend, and they set up a rope pulley to save the baby. The baby had been put out in the river by a farmer, because the mother troll switched his baby for hers.