Garden Gnome!
But I like Agoraphobic Ursine & Serf Gardner..
We could leave the wurm as is, but I thought of a problem: if you cast him, and control no other creatures, you wont have to put any creatures on top of your library. We could add the "or sacrifice" but as you've seen with the other Capricious ones I am really trying to avoid that.
I still think it wouldn't be too good (but I admit I could be wrong) that the card should be okay as:
Card Name: Capricious Wurm
Color: G
Cost: 1GG
Type: Creature - Wurm
Pow/Tgh: 4/4
Rules Text: Trample (If all the creatures blocking this creature receive lethal damage, remaining damage can be assigned to the defending player.)
When Capricious Wurm comes into play, put a creature you control on top of your library.
Flavor Text:
Rarity: U
Artist:
Number: 127/186
but perhaps, as a compromise, you could consider:
Card Name: Capricious Wurm
Color: G
Cost: 1GG
Type: Creature - Wurm
Pow/Tgh:
3/4
Rules Text: Trample (If all the creatures blocking this creature receive lethal damage, remaining damage can be assigned to the defending player.)
When Capricious Wurm comes into play, put a creature you control on top of your library.
Flavor Text:
Rarity: U
Artist:
Number: 127/186