Blue Dragon Wyrmling

Official D&D 5th Edition creature from the System Reference Document 5.2. Stats, abilities, and descriptions are faithful to the original SRD text.

The Lightning Breath is the headline feature but at CR 3 it recharges on a 5–6, so don't lead with it. Open with Multiattack to establish the physical threat, then use Breath when it recharges and you can catch at least two targets in the line. The 30-foot line is narrow — positioning matters more than with a cone. Corridors, narrow bridges, and choke points are where the wyrmling shines. In open terrain a smart party will simply spread out and neuter it.

Fly speed 60 is significant at this CR. The wyrmling should never stay on the ground if it can help it — dive, breathe, climb back out of melee range. Forcing the party to deal with a flying target that also has Multiattack is a genuine problem for low-level groups.

The Burrow speed is easy to forget but changes encounters in desert or underground settings. A wyrmling that disappears into the ground after its Breath and resurfaces on the next turn is genuinely disorienting for players. It's Lawful Evil and has an Intelligence of 12 — it's not feral. It will retreat if seriously wounded, remember enemies, and hold grudges. A wyrmling that escapes becomes a young dragon problem six months later if your campaign runs that long.

Works best as a recurring villain seed rather than a one-shot encounter.