Its Happen Every Spring

They arrive from the sea and won't quit
(They survive when 3D takes a hit)
Across screens giant critters
Give the teenagers jitters
At the drive-ins big creatures are "IT".

It Came from Beneath the Sea (Robert Gordon; 1955) features the nifty stop-motion work of Ray Harryhausen. Tentacle Week has destroyed seven days and is reaching for a fortnight.