Swirly: not rolled in the wild or from eggs.
Gengar (Swirly) is not found in the wild. Catch Gastly in Old Graveyard, then raise it to level 25 for Haunter, then trade turns it into Gengar.
Halloween Events, Mega doesn't have Shadow Tag.
Prices from the trade team's value list, in val; a Bottlecap is worth 6 val. The list prices the copies people trade for, so a plain one may not be listed.
Speed at level 100: slowest with 0 IV, 0 EVs and a −Speed nature; fastest with 31 IV, 252 EVs and a +Speed nature.