In MTG, Insects act much the same way they do in the real world: they multiply fast and can gain strength from the death of others
As far as efficiency goes, 3 damage for 1 mana is probably too much, considering Wizards of the Coast has kept it far away from Standard for a number of years
Time Walk Gamma Price: $26,400 Printed in Alpha and another member of the ultra-rare and ultra-powerful Power 9, Time Walk is a straightforward rulebreaker that lets you take an extra turn for two mana - easy to see why it's on just about every MTG banlist, and restricted to a single copy in Legacy
You can tap a huge board state of creatures to pull all the lands in your library onto the battlefield tapped with Harvest Season, and infinite token generation mills out all of your opponents thanks to Altar of the Brood
If you are able to go wide on your board and flood it with toughness 1 creatures, then you can pretty much just pay 1 mana to draw 2 cards as much as you like