This squirrel is a 3/3 Legendary Creature that costs 3 total mana, 1 green and 2 generic and reads as: Forestwalk If one or more tokens would be created under your control, those tokens plus that many 1/1 green Squirrel creature tokens are created instead
Your opponent has two choices: win a coin flip to wake up and finally play the game, or slowly bleed out while you build your board
However, the most important part of this card is that it limits the opponent by preventing them from playing item cards on their next turn
Now that you have a companion, you have something you can build around, and give yourself reliable plays
As a result, Splinter Twin eventually ended up being banned in Modern
The card is not splashy, but it reminds me quite a bit of another card previewed in a Commander deck that didn't seem all that splashy at first - Scavenging Ooze