There was no warning. A wave of green vegetation flowed up river with the tide and engulfed everything in its path. Several curious people stood on London Bridge looking down at the river. Tendrils whipped and lashed and the people were taken, only a faint scream from far below to tell they had even been there.
All along the lower lying streets on either side of the river the kelp flowed and fed. People tried to flee, piling up into panicked groups at dead ends and getting trapped by cars in rapidly forming jams. All this achieved was to give the kelp a purpose-built feeding ground, one it fell on in a frenzy of fronds and stingers.
Some people, thinking themselves safe once they had ran a good distance away from the river, turned to watch the carnage. But the kelp wasn’t about to let a potential meal go to waste. Dark buds formed all along the surface of the carpet of vegetation and with an audible, almost explosive pop, were fired in small parabolic arcs to land on the roads, bounce, and roll like soft, almost squidgy, cannonballs. Whenever they rolled up against something, be it lamppost, vehicle, or leg, they opened out, bat-wings clinging like a limpet and small tendrils lashing like whips.
Even above the sound of screaming and wailing, the predominant noise was cracking and ripping as everything made of plastic, Perspex or rubber was torn away and transported—first to the river, then, like a rock-star crowd surfing, away across the top of the fronds to be carried out towards the open sea.