"W" is for "Walverine"

Walverine

No. Enc.:  1d4 (2d4+1)
Alignment:  Neutral
Movement:  75' (25')
      —Swim:  60' (20')
Armor Class:  4
Hit Dice:  6
Attacks:  3 (2 claws, 1 bite)
Damage:  1d6 / 1d6 / 1d10+1
Save:  3
Morale:  11
Hoard Class:  None
XP:  1,820

The size of the largest Ancient big cats, walverines are savage pack hunters with ravenous appetites and nasty temperaments.  Their slick hides ripple with muscles, and razored tusks and snaggled teeth protrude from their bristly maws.

Walverines are relentless predators (with Teleportation compensating for their relative lack of speed), and a favored tactic is to bloat and expand a prey item's mass to both hobble it and generate extra meat for the pack.  And their particular suite of Mutations makes them almost impossible to kill, so it's fortunate that they exhaust easily.

Walverines are just as comfortable in the water as on land, and are known to Teleport onto—or into—seagoing (and submerged) vessels to devour the hapless crews.

Mutations:  Body Adjustment, Density Alteration (Others), Reduced Oxygen Efficiency [D], Reflective Epidermis (Heat), Teleport, Vampiric Field