Zomstrok
Source: Drop. Zomstrok is evil incarnate, the unholy mistake of someone maddened by isolation, a creation that could not be undone. Undead type. Zomstrok's ability Carpnado is a tribute/reference to WarcraftPet's post during April Fool's, in which mock-up, hybrid battle pets were "datamined" for WoD.
Zomstrok is a Warlords of Draenor battle pet dropped by undead mobs in Shadowmoon Valley, most notably Darktide Husks and Darktide Boneshell mobs.
Guide awaiting review
Travel to Shadowmoon Valley
Head to Shadowmoon Valley in Draenor and locate the coastal area where Darktide Husks and Darktide Boneshell mobs spawn.
Kill Darktide Husks
Defeat Darktide Husks and Darktide Boneshell mobs repeatedly until 
Zomstrok drops — one player reported receiving it after 283 kills.
Avoid Hallow's End Phasing
During the Hallow's End seasonal event, the Darktide mobs that drop Zomstrok are phased out in favor of Bonefleet quest content, making the pet unobtainable until the event ends.
