Petra, Sliver Slinger

{1}{t}: Add a +1/+1 counter to target creature
Creatures with +1/+1 counters on them are slivers in addition to other creature types
Creatures with +1/+1 counters on them have "All slivers have X" where X represents any abilities the creature has
"Hey chickaen I have a new deck I want to try out" -Peptor