Sea drakes straddle the line between sea dragon and sea monster—they seem almost as much fish as drake, at least judging by the art (uncredited in my edition) in the Bestiary 2. Their amphibious lifestyle serves them well—they’re not powerful enough to compete against the aquatic terrors of the open ocean, but along the coastlines and in shallow seas they are more than a match for the bunyips, crocodiles, and humanoids with whom they share the water. And their capsize ability can play merry havoc with PCs. After all, how many players choose ranks in Profession (sailor)...?
Sailors often regard ball lightning as a portent of doom. In the Queen Aliah’s case, they’re right. The ball lightning is discharge from a sea drake that was been stealthily circling the ship all evening, waiting for the dark of night to attack. To make matters worse, a pair of will-o’-wisps have unobtrusively added their glowing forms to the display, hoping to feed during the coming battle.
A yachting competition passes the Chimera’s Horn. The kobolds of the Horn see this as an opportunity, as they are eager to broker a deal with the area’s sea drakes. They seek to offer the drakes crippled, easy-to-capsize yachts if the sea drakes will serve them as steeds in future battles.
Unfulfilled oaths of alliance call a bronze dragon away from her nest. She seeks adventurers to guard her clutch from sea drake marauders while she is gone—no easy task, given their legendary mobility.
—Pathfinder Bestiary 2 109