Rydel, Brood Researcher

0: Rydel, Brood Researcher enters the battlefield with a loyalty counter for every sliver you control
0: When a sliver enters the battlefield, leaves the battlefield, or deals combat damage, put a loyalty counter on Rydel, Brood Researcher
-20: Search for x slivers where x is half the number of slivers you control rounded down and put them into play. Shuffle.