Acorn Catapult

{1}, {T}: This artifact deals 1 damage to any target. That permanent's controller or that player creates a 1/1 green Squirrel creature token.

Euru, Acorn Scrounger

When Euru, Acorn Scrounger enters, you may forage. When you do, conjure a card named Chitterspitter onto the battlefield.
Whenever one or more Squirrels you control deal combat damage to a player, you may sacrifice a token. If you do, put an acorn counter on each permanent you control named Chitterspitter.

Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)