Beluga Whale in Steal an Egg

Beluga Whale (Cosmic rarity) belongs to the Abyss Ocean zone. Abyss Ocean is zone 7 of 12 on the wiki's Biomes list; the wiki lists its entry requirement as 2.5M speed, and the nests there are watched by the Moby. You get it by carrying the Beluga Whale Egg back to your pen.

At $850K/s base income, Beluga Whale sits 3rd out of 8 in its zone — El Maja tops the Abyss Ocean at $130M/s. The listed figure assumes no mutation and a normal weight.

With a colour mutation and no size bonus, the same Beluga Whale would earn roughly: Silver ×1.2 ≈ $1.02M/s, Golden ×2.5 ≈ $2.12M/s, Rainbow ×3.5 ≈ $2.98M/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 +126k Speed, $85m, and the egg takes 12m 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.

Cosmic-rarity pets sit near the top of their zone's table; expect the nest to be contested on busy servers.