Orca

Orca hatches from the Orca Egg, a Mythic-rarity egg found in the Abyss Ocean. Abyss Ocean is zone 7 of 11 on the normal route; the wiki lists its entry requirement as ~2,5M speed, and the nests there are watched by the Moby.

The wiki lists its base income as $80K/s, which ranks it 5th of the 8 Abyss Ocean pets by base rate — El Maja tops the Abyss Ocean at $130M/s. Base rate is what a normal-size, un-mutated hatch earns; everything above that comes from the size roll and the colour mutation.

With a colour mutation and no size bonus, the same Orca would earn roughly: Silver ×1.2 ≈ $96K/s, Golden ×2.5 ≈ $200K/s, Rainbow ×3.5 ≈ $280K/s (multipliers from the wiki's Mutations page; arithmetic is ours). Add a Giant (×3) or Huge (×5) size roll on top and the numbers multiply again.

Hatching it pays a one-off reward of +99k Speed, $8m, and the egg takes 6m to grow in the pen. That reward is the reason low-income eggs are still worth stealing early: the speed bonus is what gets you into the next zone.

Mythics are the eggs other players come to steal. Bear traps around the pen are the cheap insurance (max 3, 7-second hold).