Gov, Bitter Outcast

Flanking, Menace
{2}{w}: All slivers are goblins in addition to their
other types until end of turn.
{2}{b}: All goblins are slivers in addition to their
other types until end of turn.
{1}{u}: Change the text of target spell or
permanent by replacing all instances of sliver by
goblin and all instances of goblin by sliver.
"I'll show 'em" - Gov, Bitter Outcast