Looking for a specific creature(some sort of seaslug mount)

[Dunsparce]

I remember seeing this monster that was a giant slug that some aquatic race, possibly sahaguins, used as a mount. I want to purchase one for fun, and the DM okayed it.

Edit: I also remember that it granted its rider immunities to some of its abilties

[ZamielVanWeber]

I am AFB but I am 99% sure that the monster is in MM3.

[DeltaEmil]

I am AFB but I am 99% sure that the monster is in MM3.That is correct. The monster is called the seryulin.

Incidentally, although the image does depict a sahuagin riding a seryulin, sahuagins are actually a seryulin's favorite prey, so that sahuagin really should not ever fall in front of its seryulin mount.

[Dunsparce]

So how much would one that was riding-ready cost? Or what would be a good ballpark price.

[KingSmitty]

you'd probably have to bank roll an adventuring party to go find one

[HyperDunkBarkly]

I wouldn't know how much mounts cost but I'm sure you and your DM could come up with SOMETHING to use for determining a price.

like Base Price x HD x size category or something.