1. Introduction
2. Discovery
2.1. The Supernova Legacy Survey
2.2. SNLS 06D4eu
2.3. SNLS 07D2bv
3. The Host of SNLS 06D4eu
4. Lightcurves
4.1. Blackbody Fits
4.2. Energy Requirements
5. Spectra
5.1. Observations
5.2. Theory
5.3. Analysis
6. Luminosity
6.1. $^{56}$ Ni Decay
6.2. Pair Instability
6.3. Interaction
6.4. Pulsational Pair Instability
6.5. Creation and Spin-down of a Magnetar
6.6. Accretion-driven SNe
7. Conclusions