What's your favorite summoning spell?

[Zenzei]

"The Ugly But Very Efficient Micro-Management For Winning With Minimum Losses And Ascend All The Time", I belong more to this crowd but haven't succeeded as of yet.

That said, my favorite summon is the Harbinger.
Good chassis: check
Good magic: check
Cheap: check
Low research & magic requirements: check
Good mobility: check^2

[Duncan_Frost]

CROSSBREEDING! I'm surprised it's only been mentioned once. It's so much fun! Gathering a massed horde of foul spawn around your Freak Lord is delicious, especially when there's Ettins and Chimeras striding among them.