Giant Zucchini

Now and then a Zucchini grows into a giant as it ripens: 1 in 250 times, on a tile that can start one. Only some tiles can: 9 on a 4×4 crop patch, 4 on a 3×3 crop patch and 1 on a 2×2 crop patch.

It covers 4 tiles, clearing whatever grew under it, and ends the seed's harvests. Click it 12 times to harvest it: it bursts into 16 crops of Zucchini, but pays no spare parts.