Shallop

Crew 3 (Tap any number of creatures you control
with total power 3 or more: This Vehicle becomes an
artifact creature until end of turn.)
Skulk (It can't be blocked by creatures with greater
power.)
When Shallop deals combat damage to a player
or planeswalker, create a treasure token. (It's an
artifact with "{t}, Sacrifice this artifact: Add one
mana of any color.")