Volcano Biome

Volcano, the sixth biome, needs 700K Speed and is guarded by Cerberus, a Secret pet that hatches at $8M/s from a 2-hour egg. Outside Angels & Demons, it is the only biome with two Eternal eggs in the same nest list.

Two Eternals and a Legendary that outpaces a Mythic

The full Volcano list, lowest to highest income:

• Lava Gecko (Rare, $180/s, 1m, +24k Speed)
• Lava Frog (Epic, $850/s, 1m 30s, +27k)
• Flaming Bull (Legendary, $9.5K/s, 3m, +30k)
• Lava Iguana (Legendary, $11K/s, 4m, +36k)
• Chillin Chilli (Mythic, $55K/s, 7m, +33k)
• Cerberus (Secret, $8M/s, 2h, +42k)
• Phoenix (Eternal, $85M/s, 4h 30m, +48k)
• Lava Dragon (Eternal, $100M/s, 5h, +60k)

Note the Lava Iguana: its egg is shorter than the Chillin Chilli's (4 minutes against 7) and its Speed reward is bigger (+36k against +33k), even though the Mythic earns five times more. If Speed is what you are after, the Iguana is the better Legendary-tier pick. At the top, the Lava Dragon edges out the Phoenix by $15M/s for an extra 30 minutes of growth.

A 1.8M gap to Abyss Ocean

Abyss Ocean sits at 2.5M Speed, so leaving Volcano means adding 1.8M. Every Volcano egg together adds 300k. Counting egg rewards only, you would need 75 Lava Geckos (the most Speed per second of growth, about 400), 50 Lava Iguanas or 30 Lava Dragons. Treadmills carry the rest: a Flaming Bull reward ($950k) is already close to four times the Flame Treadmill's price, and a single Phoenix reward ($8.5b) pays for The Freeze Treadmill ($3B, +100 Speed per step) with room to spare.

Volcano in two Rift banners

Volcano is one of only two biomes that feed both the Riftborn and Riftbeasts banners (Abyss Ocean is the other). On the Rift Sacrifice lists, Lava Gecko and Lava Frog are Easy, and Flaming Bull, Lava Iguana and Chillin Chilli are Medium in both banners. Since the banner changes roughly every 3 hours, Volcano pets are useful for sacrifices more often than pets from biomes tied to a single banner.