Due to Alpacky's high range, Radiant Aphrodite is recommended as her range is 600 (longer than Alpacky) and she inflicts triple damage against aliens.
Li'l Nyandam is a non-uber alternative, as he also outranges Alpacky.
If you have no units that outrange her, use tanky melee units like Jamiera/Crazed Mythical Titan. Save your cat cannon for when she survives the lethal strike. By then, her ability will be activated, and she can deal extreme damage. Use your cat cannon to finish her off. However, if you are unlucky, the ability will be active before the lethal strike. If that happens, use units with good speed like Crazed Cow or even Valkyrie could work.
WARNING! Remember that when she survives the lethal strike, her damage goes from 1,750 to 17,500!
Time between attacks
550 (area attack)
Survives a lethal strike (100%); Attack power will increase by 900% at 1% health; Good At Castle Destruction (4x damage to Cat Base)
This enemy's description says that Alpacky is just Camelle, but also refers to it as "her" (?), while Camelle is a he.