Dracunculus

例句：

1. 1. The hydra is a fascinating creature with many tentacles.
   这个水母有多个触手，非常迷人。
2. 2. The hydra was once thought to be immortal, but it has since been proven to have a limited lifespan.
   这个水母曾被认为永生不死，但后来被证明寿命有限。
3. 3. The hydra is now considered a rare and endangered species due to habitat loss and pollution.
   由于栖息地丧失和污染，这个水母现在被认为是稀有且濒危的物种。