Cheese in dairy plant?

[Conga Lyne]

I used VIII - Mad Groove as my first pick on dairy plant and noticed a wheel of cheese moved to me, upon picking it up a pack of giant werewolves and medusa spawned around me.
I killed them with pentagram and i'm unsure if they drop anything, or if they tie in to any secret, but they exist

[couchalmark]

Killing the werewolves unlocks the secret character Minnah.

[A̵̡͆ ̷͝Ĺ̷̺ ȋ̶v ?]

Check your character selection, you might find a new hairy friend.
(if you don't, maybe you can't kill them with pentagram but I doubt it)

[Dr Koschei]

As Couchalmark said, it unlocks a werewolf character with an evolved whip weapon.
In terms of actual loot? Red XP gems was all I noticed.

[ThatGuyCDude]

Originally posted by A̵̡͆ ̷͝Ĺ̷̺ ȋ̶v ?:

Check your character selection, you might find a new hairy friend.
(if you don't, maybe you can't kill them with pentagram but I doubt it)

You can't, Pentagram 'erases' them which doesn't count as a kill for the unlock (I know, that's what I tried the first time I tried it). You have to kill them with other weapons or hold off until you have Glorious Moon or a high-enough level Pentagram that the erasure doesn't happen.

[soulblade128]

if you get lucky enough, I think the pick-up cross item works, since it kills instead of erases, unless that's wrong... in which case never mind.