Deep Delvers

Tunnel: Each round, Deep Delvers can Tunnel or Surface (not both) as an Instant. When Tunneled, flip the card over; they cannot interact with anything on the surface. When they Attack the same round they Surface, Deep Delvers have Stealth.
Eyes of Madness: when a creature battles Deep Delvers, it must either take -1/-1, or roll a die. On
1-2, they act normally. On 3-4, they do nothing.
On 5-6, they Attack themselves.