[quote=@Doc Doctor]
[@MelonHead]

In Slimy's profile, it says it "makes no noise" in the behavior section.
[/quote]

That's not suitable information to warrant having the ability, not to mention it's in completely the wrong section. Nothing can move completely silently without some sort of magic, nothing of that sort is mentioned in the sheet, therefore it is not silent while moving. 

If you want a character to have an ability (moving silently being a pretty useful ability and certainly not something that should be mentioned off the cuff in an inappropriate area with no explanation) it should be clearly labelled in the abilities section. The only exception is things that are considered innate, such as the fact that your character can feel, or hear or other things of non-supernatural capacity. 

That being said, it's up to Pollen's digression I guess if that's enough to warrant Higan being unable to hear the creature.