Sandworm

Sandworm is a large, slow creature that lives within the Sabasa Desert. Her size is very large, as Luka remarks “even her tongue is bigger than [his] entire body”. She ambushes men within the desert and sucks them dry like candy.

As Luka travels the Safaru Ruins in search of Gnome, he encounters another of her mud dolls, which ends up leading to the Sandworm. Despite her intimidating size, he manages to seal her into a tiny sandworm.

Encyclopedia Entry
''“A huge monster that lives in arid regions. It usually hides under the sand, but when it senses the vibrations of a moving human, it will attack them. forcing the man into her mouth, she will suck on them like a piece of candy. Her giant tongue can quickly force a man to orgasm. Once the man has reached orgasm, she will begin to to use her tongue to suck and lick up all the semen, forcing the man to continually ejaculate. Once she sucks out everything from the man, she will burrow back under the sand to await her next meal. Though she is very slow and absentminded, you cannot be careless around her.''

''Most desert monsters greedily suck up men’s fluids to slake their thirsts. Great care needs to be taken when traveling through the desert, since being caught by a monster usually entails certain death.”''

Battle Overview
Being an incredibly large monster, Sylph is impractically useless in this battle. Fortunately, despite her intimidating size, she is very slow and often dazes off, allowing Luka to score easy hits with no problem. Her only attacks are those caused by binds; she'll use Mouth Hold on him every once in a while and violate his penis with her tongue. Instead of using futile Struggles, Attacking three times is the key to breaking free. Simply put, constantly use Death Sword Chaos Star and keep Attacking.

If Luka reaches ejaculation, she holds him as she licks his penis, then forces his lower half into her mouth as her tongue continues violation. Finally, all his semen is extracted, resulting his death as his shriveled corpse drowns in the sand.