The werecats were a trio of monsters on Moonscar Island. They could prolong their lives and stay immortal only by draining the lives of others at the time of the harvest moon.
They resembled cat-like humanoids completely covered with fur and two ears along with a tail. They also had two yellow cat-like eyes, and razor sharp teeth to match their razor sharp claws.
In their true forms, they are very savage. They would go through any lengths to keep their immortality by sacrificing innocent lives.
Powers and abilities
Once transformed, the werecats gained super strength and could run very fast, that Shaggy and Scooby could hardly outrun them. They had the power to absorb victims' souls to preserve their own immortality. The victims, however, were rendered zombies as a result.
Two hundred years prior, Morgan Moonscar and his crew of pirates destroyed the village of which Simone and Lena were a part. The pirates killed the settlers, though Simone and Lena escaped. They sought revenge by uttering a curse on the pirates, and their cat god granted their wish by turning them into cat creatures. The women got their revenge by draining the pirates' life force, but they discovered they were also cursed in that they had to drain others' life force every harvest moon to survive.
They did this for the next 200 years, with Lena using her charm to lure outsiders when necessary. Simone and Lena inexplicably passed the curse on to a willing Jacques, who served as ferry driver to bring victims to the island.
Scooby-Doo on Zombie Island
Lena lured the gang to Moonscar Island, and Jacques brought them there via ferry. At midnight, Lena and Simone used voodoo dolls to restrain the gang against the dungeon wall. They partially transformed into cat creatures and Simone explained that they will drain the gang's life force to preserve their immortality and told their story to the gang.
At the same time, Jacques transformed and chased Scooby and Shaggy across the island in an attempt to drain them. He briefly caught the two, but thanks to the zombies, they escaped to the dungeon. Just as Lena and Simone were seconds from draining the gang, Scooby and Shaggy tumbled in and knocked them down. They then fully transformed (growing fur, claws on their hands and feet, a tail, and tattering their clothes and shoes) and chase Scooby and Shaggy. Jacques reappeared and nearly drains Shaggy, who got away. Lena and Simone briefly drained them, though Velma and Daphne interrupted that by using the voodoo dolls on the cat creatures.
The three cat creatures backed the gang into a corner, finally ready to drain them. Suddenly, their bodies started smoking as the werecats let out pained expressions. Velma observed that midnight passed and the curse was broken. The cat creatures' and zombies' bodies disintegrated as the victims' souls were released and could rest in peace.