Emperor Crab

Capture a P/P Emperor Crab in the Briny Muck to the south of the Dread Wastes. The Emperor Crab may appear as the lead pet, or as backup to the Rapana Whelks in the area.

These are such a useful tanky species that you might pick up a second, or a H/H breed, as well while you're there.

The Emperor Crab is a tanky pet, that will shield and heal itself, and survive a long time with little need for healing between battles.

Keep your Shell Shield up at all times, and use your Renewing Mists when available. Use Surge (usually) or Snap otherwise.

The most common use is to start with Shell Shield, follow with Renewing Mists, and use Surge when those don't need to be refreshed. Against Critters specifically, you will likely prefer Snap for the family type advantage, but otherwise the speed of the priority move Surge is usually more useful.

In some cases, you may prefer Healing Wave to time a big heal. Whirlpool is often used in Tamer strats to be timed with a debuff or other large hit.

There are many other Crabs with the same moveset, but the P/P Emperor Crab with its 357 Power has much more power than any other, giving its shields and heals extra effectiveness.