Eclipse's Level Up Ability works well with all rooms that can either destroy themselves, or other rooms, particularly when those rooms that are destroyed have another room under them in a stack. Rooms like Bottomless Pit, The Crushinator and Boulder Ramp are examples of rooms that can destroy themselves, or others. Rooms that are uncovered that also have an uncover effect also work well with this Boss' ability.
The only drawback to this ability is that it requires quite a bit of room stacking, and a room/s that can destroy themselves or others, so it may be best to build up room stacks before using this Boss' ability.
Eclipse, The Charrer of Souls was formerly known as TBD, The Black Dragon. The Brothers auctioned the naming rights on eBay, in a manner similar to the Boss Monster Base Set Kickstarter, in which the highest prize was for the naming rights to the Golden Dragon, now known as Kirax. All proceeds made for the naming rights were to go to charity.
Eclipse bears a striking resemblance to Ridley of Metroid fame. It also is a winged dragon with larger hind-legs than fore-limbs which make the monster appears (in part) bi-pedal, also the head, wings, and tail are very stylistically similar.