In cultivation since the 1800's, this rare form is still extremely hard to come by. Fagus syl. 'Cristata' can eventually become a 20-30' tree, but is very slow growing so this 12/14'H x 5/6' will be easily manageable in your garden for quite a long time. The non-beech like leaves cluster together on congested, contorted clumps.
Fagus sylvatica 'Cristata'
Fagus syl. 'Cristata' leaf detail